
















/ • 

















* 














































































I 


















* 

































0 




















SUMMARY TECHNICAL REPORT 
OF THE 

NATIONAL DEFENSE RESEARCH COMMITTEE 


This document contains information affecting the national defense of 
the United States within the meaning of the Espionage Act, 50 U.S.C., 
31 and 32, as amended. Its transmission or the revelation of its contents 
in any manner to an unauthorized person is prohibited by law. 

This volume is classified RESTRICTED in accordance with security 
regulations of the War and Navy Departments because certain chap¬ 
ters contain material which was RESTRICTED at the date of printing. 
Other chapters may have had a lower classification or none. The reader 
is advised to consult the War and Navy agencies listed on the reverse 
of this page for the current classification of any material. 


RESTRICTED 


Manuscript and illustrations for this volume were prepared 
for publication by the Summary Reports Group of the 
Columbia University Division of War Research under con¬ 
tract OEMsr-1131 with the Office of Scientific Research and 
Development. This volume was printed and bound by the 
Columbia University Press. 

Distribution of the Summary Technical Report of NDRC 
has been made by the War and Navy Departments. Inquiries 
concerning the availability and distribution of the Summary 
Technical Report volumes and microfilmed and other refer¬ 
ence material should be addressed to the War Department 
Library, Room 1A-522, The Pentagon, Washington 25, D. C., 
or to the Office of Naval Research, Navy Department, Atten¬ 
tion : Reports and Documents Section, Washington 25, D. C. 


Copy No. 

143 


This volume, like the seventy others of the Summary Tech¬ 
nical Report of NDRC, has been written, edited, and printed 
under great pressure. Inevitably there are errors which have 
slipped past Division readers and proofreaders. There may 
be errors of fact not known at time of printing. The author 
has not been able to follow through his writing to the final 
page proof. 

Please report errors to: 

JOINT RESEARCH AND DEVELOPMENT BOARD 
PROGRAMS DIVISION (STR ERRATA) 

WASHINGTON 25, D. C. 

A master errata sheet will be compiled from these reports 
and sent to recipients of the volume. Your help will make 
this book more useful to other readers and will be of great 
value in preparing any revisions. 


RESTRICTED 


SUMMARY TECHNICAL REPORT OF DIVISION 6, NDRC 


VOLUME 4 


METHODS AND DEVICES 
DEVELOPED FOR THE 
SELECTION AND TRAINING 
OF SONAR PERSONNEL 


OFFICE OF SCIENTIFIC RESEARCH AND DEVELOPMENT 
VANNEVAR BUSH, DIRECTOR 

NATIONAL DEFENSE RESEARCH COMMITTEE 
JAMES B. CONANT, CHAIRMAN 

DIVISION 6 

JOHN T. TATE, CHIEF 


WASHINGTON, D. C., 1946 


RESTRICTED 



NATIONAL DEFENSE RESEARCH COMMITTEE 


James B. Conant, Chairman 
Richard C. Tolman, Vice Chairman 
Roger Adams Army Representative 1 

Frank B. Jewett Navy Representative 2 

Karl T. Compton Commissioner of Patents 3 

Irvin Stewart, Executive Secretary 


1 Army representatives in order of service: 
Maj. Gen. G. V. Strong Col. L. A. Denson 


Maj. Gen. R. C. Moore 
Maj. Gen. C. C. Williams 
Brig. Gen. W. A. Wood, Jr. 


Col. P. R. Faymonville 
Brig. Gen. E. A. Regnier 
Col. M. M. Irvine 


Col. E. A. Routheau 


-Navy representatives in order of service: 

Rear Adm. H. G. Bowen Rear Adm. J. A. Furer 
Capt. Lybrand P. Smith Rear Adm. A. H. Van Kearen 
Commodore H. A. Schade 
3 Commissioners of Patents in order of service: 
Conway P. Coe Casper W. Ooms 


NOTES ON THE ORGANIZATION OF NDRC 


The duties of the National Defense Research Committee 
were (1) to recommend to the Director of OSRD suitable 
projects and research programs on the instrumentalities 
of warfare, together with contract facilities for carry¬ 
ing out these projects and programs, and (2) to admin¬ 
ister the technical and scientific work of the contracts. 
More specifically, NDRC functioned by initiating re¬ 
search projects on requests from the Army or the Navy, 
or on requests from an allied government transmitted 
through the Liaison Office of OSRD, or on its own con¬ 
sidered initiative as a result of the experience of its 
members. Proposals prepared by the Division, Panel, or 
Committee for research contracts for performance of the 
work involved in such projects were first reviewed by 
NDRC, and if approved, recommended to the Director of 
OSRD. Upon approval of a proposal by the Director, a 
contract permitting maximum flexibility of scientific 
effort was arranged. The business aspects of the con¬ 
tract, including such matters as materials, clearances, 
vouchers, patents, priorities, legal matters, and admin¬ 
istration of patent matters were handled by the Execu¬ 
tive Secretary of OSRD. 

Originally NDRC administered its work through five 
divisions, each headed by one of the NDRC members. 
These were: 

Division A—Armor and Ordnance 
Division B—Bombs, Fuels, Gases, & Chemical Problems 
Division C—Communication and Transportation 
Division D—Detection, Controls, and Instruments 
Division E—Patents and Inventions 


In a reorganization in the fall of 1942, twenty-three 
administrative divisions, panels, or committees were 
created, each with a chief selected on the basis of his 
outstanding work in the particular field. The NDRC 
members then became a reviewing and advisory group 
to the Director of OSRD. The final organization was as 
follows: 

Division 1—Ballistic Research 

Division 2—Effects of Impact and Explosion 

Division 3—Rocket Ordnance 

Division 4—Ordnance Accessories 

Division 5—New Missiles 

Division 6—-Sub-Surface Warfare 

Division 7—Fire Control 

Division 8—Explosives 

Division 9—Chemistry 

Division 10—Absorbents and Aerosols 

Division 11—Chemical Engineering 

Division 12—Transportation 

Division 13—Electrical Communication 

Division 14—Radar 

Division 15—-Radio Cooi’dination 

Division 16—-Optics and Camouflage 

Division 17—Physics 

Division 18—War Metallurgy 

Division 19—Miscellaneous 

Applied Mathematics Panel 

Applied Psychology Panel 

Committee on Propagation 

Ti-opical Deterioration Administrative Committee 


iv 


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1015 


490948 





NDRC FOREWORD 


A S events of the years preceding 1940 re- 
u vealed more and more clearly the serious¬ 
ness of the world situation, many scientists in 
this country came to realize the need of organ¬ 
izing scientific research for service in a national 
emergency. Recommendations which they made 
to the White House were given careful and sym¬ 
pathetic attention, and as a result the National 
Defense Research Committee [NDRC] was 
formed by Executive Order of the President in 
the summer of 1940. The members of NDRC, 
appointed by the President, were instructed to 
supplement the work of the Army and the Navy 
in the development of the instrumentalities of 
war. A year later, upon the establishment of the 
Office of Scientific Research and Development 
[OSRD], NDRC became one of its units. 

The Summary Technical Report of NDRC is 
a conscientious effort on the part of NDRC to 
summarize and evaluate its work and to present 
it in a useful and permanent form. It comprises 
some seventy volumes broken into groups cor¬ 
responding to the NDRC Divisions, Panels, and 
Committees. 

The Summary Technical Report of each Divi¬ 
sion, Panel, or Committee is an integral survey 
of the work of that group. The first volume of 
each group’s report contains a summary of the 
report, stating the problems presented and the 
philosophy of attacking them, and summarizing 
the results of the research, development, and 
training activities undertaken. Some volumes 
may be “state of the art” treatises covering 
subjects to which various research groups have 
contributed information. Others may contain 
descriptions of devices developed in the labora¬ 
tories. A master index of all these divisional, 
panel, and committee reports which together 
constitute the Summary Technical Report of 
NDRC is contained in a separate volume, which 
also includes the index of a microfilm record of 
pertinent technical laboratory reports and ref¬ 
erence material. 

Some of the NDRC-sponsored researches 
which had been declassified by the end of 1945 
were of sufficient popular interest that it was 
found desirable to report them in the form of 
monographs, such as the series on radar by 
Division 14 and the monograph on sampling 
inspection by the Applied Mathematics Panel. 
Since the material treated in them is not du¬ 


plicated in the Summary Technical Report of 
NDRC, the monographs are an important part 
of the story of these aspects of NDRC research. 

In contrast to the information on radar, 
which is of widespread interest and much of 
which is released to the public, the research on 
subsurface warfare is largely classified and is 
of general interest to a more restricted group. 
As a consequence, the report of Division 6 is 
found almost entirely in its Summary Technical 
Report, which runs to over twenty volumes. 
The extent of the work of a Division cannot 
therefore be judged solely by the number of 
volumes devoted to it in the Summary Technical 
Report of NDRC: account must be taken of 
the monographs and available reports published 
elsewhere. 

Any great cooperative endeavor must stand 
or fall with the will and integrity of the men 
engaged in it. This fact held true for NDRC 
from its inception, and for Division 6 under the 
leadership of Dr. John T. Tate. To Dr. Tate and 
the men who worked with him—some as mem¬ 
bers of Division 6, some as representatives of 
the Division’s contractors—belongs the sincere 
gratitude of the Nation for a difficult and often 
dangerous job well done. Their efforts contrib¬ 
uted significantly to the outcome of our naval 
operations during the war and richly deserved 
the warm response they received from the Navy. 
In addition, their contributions to the knowl¬ 
edge of the ocean and to the art of oceano¬ 
graphic research will assuredly speed peacetime 
investigations in this field and bring rich bene¬ 
fits to all mankind. 

The Summary Technical Report of Division 6, 
prepared under the direction of the Division 
Chief and authorized by him for publication, 
not only presents the methods and results of 
widely varied research and development pro¬ 
grams but is essentially a record of the un¬ 
stinted loyal cooperation of able men linked in 
a common effort to contribute to the defense 
of their Nation. To them all we extend our 
deep appreciation. 

Vannevar Bush, Director 
Office of Scientific Research and Development 

J. B. Conant, Chairman 
National Defense Research Committee 


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v 























































































FOREWORD 


F ollowing the organization of Division C in 
the spring of 1941, it soon became apparent 
that the Division could offer valuable assistance 
to the Navy in activities other than those 
originally contemplated. Among these was the 
selection and training of personnel, the subject 
of this report. In October 1941, Captain Lybrand 
Smith, Assistant Coordinator of Research and 
Development, wrote to Dr. F. B. Jewett, Chair¬ 
man of Division C, in part as follows: 

Everybody concurs in the opinion that it is desirable 
to study and formulate aptitude tests for personnel who 
are to be trained for the operation of sonic and super¬ 
sonic apparatus and to formulate improved training 
programs for such persons. Therefore, it is requested 
that NDRC undertake this work. 

This request was formally accepted by the 
NDRC in November 1941 and assigned to Sec¬ 
tion C-4. Steps were promptly taken to organize 
this work. At the request of Dr. J. T. Tate, 
Dr. G. P. Harnwell, serving as Technical Aide, 
undertook to review the problem and to recom¬ 
mend plans for NDRC participation. Largely 
on the basis of Dr. Harnwell’s findings, a com¬ 
mittee on the Selection and Training of Sound 
Operators was appointed in December 1941 to 
study various aspects of the training program 
in cooperation with Navy personnel and to 
recommend action to the Division. Members of 
the Committee were Dr. Viteles, Dr. Wever, Dr. 


Wilks, Dr. Fry, and Mr. Shea, with Dr. Harn¬ 
well as chairman. 

An initial training group was set up at the 
University of California laboratory at San 
Diego. As the work of the Division expanded, 
training groups were established at other 
laboratories and the scope of activities broad¬ 
ened. During 1942 and 1943 the major emphasis 
of the program was on the selection and train¬ 
ing of ASW sonar personnel, whereas during 
1944 and early 1945, equal or even greater 
emphasis was given to the training of sub¬ 
marine personnel. 

The following volume summarizes the prin¬ 
cipal activities and accomplishments of the 
Selection and Training groups in the field of 
subsurface warfare. That these civilian groups 
were able to make significant contributions to 
what had always been considered purely mili¬ 
tary activities is a tribute to the wise guidance 
of Dr. Harnwell and his associates. The Di¬ 
vision also wishes to record its appreciation to 
Dr. Harnwell, as well as to Dr. W. D. Neff and 
Dr. M. C. Towner, for the collection and prep¬ 
aration of the material included in this volume. 
In this work, they were assisted by the editorial 
staff of the Columbia University Summary Re¬ 
ports Group. 

John T. Tate 
Chief, Division 6 


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Vll 



































































PREFACE 


T his volume, dealing with methods and 
means for selecting and training Naval 
sonar officers, operators, and maintenance men, 
summarizes activities undertaken by a number 
of laboratories and independent groups operat¬ 
ing under Division 6. Unfortunately, limitations 
in time and available personnel have not per¬ 
mitted the preparation of an integrated well- 
balanced text on this subject. Consequently, the 
following pages must be regarded rather as a 
final report of the groups and laboratories con¬ 
cerned. It is hoped, however, that much of value 
will be derived from the volume, both by mili¬ 
tary and by civilian groups having kindred 
problems in the training of large groups to 
perform specialized tasks. 

The volume is divided into two parts. The 


first covers the methods of selection and train¬ 
ing, and was prepared by Dr. W. D. Neff, with 
the assistance of Dr. W. L. Jenkins and Dr. 
R. L. French of the Columbia University 
laboratory at New London. Basic material was 
furnished by Dr. J. Morris, Dr. Hartig, and 
Dr. Ford. 

The second part of the volume describes in 
some detail the physical devices developed by 
the several laboratories to serve as training aids 
for individual or group instruction. Most of 
this material was prepared originally under the 
direction of Dr. Towner, with final editing by 
the staff of the Columbia University Summary 
Reports Group. 

J. S. Coleman 


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IX 

























































































CONTENTS 


PART I 

SELECTION AND TRAINING OF PERSONNEL 

CHAPTER PAGE 

1 Introduction. ] 

2 Selection of Antisubmarine Warfare Personnel .... 9 

3 Training of Antisubmarine Warfare Personnel .... 19 

4 Selection of Submarine Personnel.40 

5 Training of Submarine Personnel.45 

PART II 

DEVICES USED AS TRAINING AIDS 

6 Trainers for Antisubmarine Warfare Sonar Operators . . 57 

7 Recorder Operator Trainers.82 

8 Classroom Attack Teacher Modifications.89 

9 Shipboard Trainers for Sound Operators and Attack Teams 102 

10 Practice Target Equipment.133 

11 Training Equipment for Antisubmarine Warfare Sonar Main¬ 
tenance Personnel.148 

12 Trainers for Aircraft Personnel Using Sonar Equipment . . 162 

13 Miscellaneous Trainers and Demonstrators.167 

14 Trainers for Submarine Sonar Operators.175 

15 Trainers and Demonstrators for Submarine Officers . . . 193 


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xi 









CONTENTS 


xii 


Glossary.213 

Bibliography.215 

Contract Numbers.225 

Service Project Numbers.226 

Index.227 


RESTRICTED 








Chapter 1 

INTRODUCTION 


11 SELECTION AND TRAINING OF 
ANTISUBMARINE PERSONNEL 

At the first meeting with the Committee 
on Selection and Training, December 4, 
1941, representatives of the Navy very fully 
and helpfully outlined the problems faced in 
selecting and training a sufficient number of 
sonar operators to meet their rapidly increas¬ 
ing requirements. By the time of the second 
meeting, January 2, 1942, the Navy had made 
new plans calling for a several fold increase in 
our antisubmarine warfare [ASW] forces, and 
the problems of selection and training had be¬ 
come still more urgent. 


Selection 

The development of methods whereby better 
students could be selected for the sound oper¬ 
ator courses given at the West Coast Sound 
School, San Diego, and the Fleet Sound School, 
Key West, was undertaken as the most imme¬ 
diate means of improving the quality of sonar 
operators. At a later date, the selection of 
maintenance men was studied, and, still later, 
that of sonar officers. 

Sonar Operators. Members of the committee 
visited the Navy sound schools and made a pre¬ 
liminary analysis of the sonar operator’s job. 
A number of standard aptitude tests which 
were readily available were administered ex¬ 
perimentally to sonar operator classes entering 
the schools. An initial selection scheme using 
the tests' 1 which best predicted success in the 
operator course was put into effect at naval 
training centers in April 1942. In spite of the 
emergency haste with which this first test bat¬ 
tery was chosen, results justified its adoption; 
the number of student failures was immediately 
reduced and the general caliber of the men sent 
to the school was quite obviously raised. 

Research to improve the initial selection plan 

a The Navy GCT, the Bennett Mechanical Compre¬ 
hension Test, and the Pitch and Tonal Memory Tests 
from the Seashore Measures of Musical Talent. 


was continued throughout 1942, 1943, and part 
of 1944. Studies were made of additional fac¬ 
tors such as age, amount of education, near¬ 
vision, and threshold hearing to determine their 
importance in operator selection. A final selec¬ 
tion scheme, adopted in 1944, was a somewhat 
refined version of the original scheme, with 
added emphasis on the auditory tests. Repeated 
checks indicated that the sonar operator selec¬ 
tion methods were successful in choosing men 
who could successfully pass the sonar operator 
courses. 

Maintenance Men. In the summer of 1942, 
research on selection of sonar maintenance men 
was started independently at the two sound 
schools. The problem was to pick the graduates 
of the sonar operator course who were most 
likely to be successful in the maintenance 
course. Essentially similar procedures were 
adopted at both San Diego and Key West. Stand¬ 
ing in the operator course, grades on tests of 
mathematical and mechanical comprehension, 
years of education, and evidence of interest in 
radio and electricity were found to be significant 
factors. At both schools, the selection methods 
adopted reduced substantially the number of 
failures in the sonar maintenance course. 

Sonar Officers. In May 1943 Division 6 was 
asked to extend its work to include research on 
the selection of sonar officers. Two studies were 
made, the first completed in September 1943 
and the second in July 1944, but neither gave 
conclusive results. The attempt to validate a 
test battery was hampered by the difficult con¬ 
ditions under which tests had to be adminis¬ 
tered, by the lack of reliable criteria, and by 
the preselection of the experimental groups. A 
tentative selection scheme was suggested but 
the demands of the sonar officer training pro¬ 
gram did not warrant its adoption. 


112 Training Assistance to Navy Sound 
Schools 

Concurrently with the research on selection, 
assistance was being given in developing the 


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I 



2 


INTRODUCTION 


training programs at the sound schools in San 
Diego and Key West. Early in 1942, personnel 
to assist in development of training methods 
were assigned to both schools and a section of 
the University of California Division of War 
Research [UCDWR] laboratory at San Diego 
was given over to the design of synthetic train¬ 
ers. During 1943 the work of these groups 
reached a peak; it continued, but at a lower 
priority, through 1944 and the spring of 1945. 

Curriculum Planning. Directly or indirectly, 
the training personnel at both schools made a 
continuous effort to revamp course schedules. 
At first, their efforts were limited to specific 
suggestions for correcting obvious defects, such 
as the elimination of unsupervised study and 
needless stand-by time. Later, as they became 
more intimately acquainted with the problems 
of the schools, the training groups worked di¬ 
rectly with instructors in planning major revi¬ 
sions in course schedules. An increase in the 
supply of standard equipment and synthetic 
training devices permitted greater emphasis to 
be placed on operating drills and laboratory 
work. 

Achievement Testing. The inadequacy of the 
methods being used to measure student achieve¬ 
ment first became manifest when school grades 
were examined as criteria for validating selec¬ 
tion tests. Reliable measures of student knowl¬ 
edge were soon provided in the form of 
standardized objective written examinations, 
but measures of student performance were 
more difficult to achieve. The better synthetic 
trainers were designed so as to provide direct 
measures of performance. For other trainers 
and for standard equipment on training ships, 
checking systems were devised which enabled 
the instructor to check or rate the student on 
each part of a series of complex operations. 
The checking systems were not only useful for 
grading but also for showing up weak spots in 
training. 

Instructor Training. Assistance in the train¬ 
ing of Navy instructors was largely informal. 
Members of the training groups helped in¬ 
structors plan their lectures and drills and 
coached them in effective methods of presenta¬ 
tion. The introduction of new equipment and 
of new synthetic training devices provided 
many opportunities to demonstrate better teach¬ 


ing methods. The effectiveness of instructor 
training was severely limited, however, by the 
system of instructor rotation. Retention of good 
instructors for longer periods would have per¬ 
mitted more thorough training and greater 
teaching efficiency in the schools. 

Preparation of Training Aids. Instruction 
books, phonograph recordings, slides and films, 
wall charts, and miscellaneous devices were 
produced in quantity. The laboratories provided 
instruction books on operation and maintenance 
of new equipment and instructor’s handbooks 
for synthetic trainers. The groups stationed at 
the schools assisted in the preparation of more 
general textbooks for classroom use. 

Perhaps the most valuable training aids de¬ 
veloped were phonograph recordings of under¬ 
water sounds. Some 300 finished recordings 
were made for ASW sonar training. The first 
of these contained examples to be used for class¬ 
room demonstrations; then, in order to increase 
student participation, drill and test recordings 
were prepared; and ultimately, special trainers 
were designed so that an instructor could con¬ 
tinuously monitor the students during record¬ 
ing drills. 

Construction of Synthetic Trainers. In order 
to overcome the serious shortage of practice 
equipments, first efforts were concentrated on 
design of synthetic trainers which could be 
turned out in quantity and in a hurry. Bearing 
teachers which simulated many of the opera¬ 
tions of the standard sonar stack were pro¬ 
duced during 1942. Experience with these first 
individual trainers led to the development dur¬ 
ing 1943 and 1944 of group trainers, each hav¬ 
ing a central control station from which an 
instructor could direct and monitor a group of 
10 to 20 students. The later synthetic trainers 
also provided more realistic sounds and better 
methods of scoring performance. 


11,3 Assistance to Navy Activities Other 
Than Sound Schools 

Although much of the assistance given by 
the Division 6 selection and training groups 
concerned the two sound schools, work outside 
the schools grew to occupy an important place 
in ASW sonar training. In 1943, a training rep- 


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SELECTION AND TRAINING OF ANTISUBMARINE PERSONNEL 


3 


resentative was assigned to the Readiness Sec¬ 
tion, COMINCH 10th Fleet. Later that year and 
during early 1944, similar liaison men were 
assigned to COTCLant and ComDesPac. Mem¬ 
bers of the school and laboratory training 
groups also made frequent visits to other train¬ 
ing activities to assist in the installation of 
training equipment and in the initiation of 
programs for use of new synthetic trainers. 


1 ' 1 ' 4 Training Programs to Introduce 
New Laboratory Developments 

The laboratories of Division 6 were primarily 
engaged in research leading to the development 
of new devices for combat use. When the very 
first units of such devices were produced and 
turned over to the Navy, it became evident 
that the laboratories themselves would have to 
take an active part in initiating training pro¬ 
grams for the Service personnel who were to 
operate and maintain the new equipment. 

It was desirable to use the knowledge and 
experience of the research engineers without 
burdening them with the actual tasks of train¬ 
ing. Consequently, groups were organized at 
the laboratories to work specifically on the prob¬ 
lems of training. It was the function of these 
groups to plan suitable training courses, pre¬ 
pare necessary training aids and devices, and 
provide the field services needed to introduce 
the training courses at Navy activities. 

BDI Training. The bearing deviation indi¬ 
cator [BDI], providing accurate and continu¬ 
ously centered target bearings, was developed 
by the Harvard Underwater Sound Laboratory 
[HUSL]. The introduction of BDI necessitated 
suitable training for sonar operators, mainte¬ 
nance men, and officers. For operators, experi¬ 
mental models were made of three different 
synthetic trainers, one of which was produced 
in quantity. Maintenance courses for field en¬ 
gineers who were supervising BDI installations 
were given at the laboratory, and a course for 
ASW specialists was outlined in collaboration 
with the Antisubmarine Warfare Instructors’ 
School [ASWIS], Boston. Experiments to de¬ 
velop conning procedures using center bearings 
were conducted by laboratory personnel in col¬ 
laboration with AsDevLant. 


ERSB Programs. The expendable radio sono 
buoy [ERSB] was an airborne antisubmarine 
device developed by the Columbia University 
Division of War Research [CUDWR] labora¬ 
tory. To insure the effective use of this device, 
an extensive training program was conducted 
by laboratory training and development groups. 
During late 1942 and 1943, before production 
units of ERSB were in use, instruction manuals 
and recordings were prepared and a training 
course for several groups of instructors was. 
given. Later a slide film describing the buoy 
equipment and its use was produced and dis¬ 
tributed. Instruction books and recordings were 
revised and reissued. 

An even more important factor in training 
Navy personnel who used ERSB equipment was 
the widespread efforts of a special ERSB field 
group. These men provided both engineering 
and training assistance. They visited all bases 
where buoy equipment was in use, started train¬ 
ing courses, helped install equipment, and made 
flights to try it out and to give crew training. 
They also made trips on carriers into combat 
zones in order to service equipment and train 
the plane crews using it. Their activities car¬ 
ried them to bases in the Atlantic, Mediter¬ 
ranean, Caribbean, and Pacific. 

In 1944 a sono buoy school was established 
by ComAirLant at Norfolk, Virginia. A syn¬ 
thetic trainer was constructed for this school, 
instructors were trained, and assistance was 
given in planning courses. 

During 1944 and early 1945, in anticipation 
of its Service use, a training program for a 
modified buoy was started. By this time, how¬ 
ever, the job was greatly simplified, since the 
ComAirLant school was ready to give training 
courses and the Aircraft Coordinating Group, 
BuShips was carrying on the work formerly 
done by the ERSB field group. Instruction 
books, recordings, a movie, and a synthetic 
trainer were produced and turned over to these 
groups for use, and a special course for in¬ 
structors was conducted at the New London 
laboratory. 

BT Program. The bathythermograph [BT] 
developed by Woods Hole Oceanographic Insti¬ 
tution [WHOI] made possible the prediction of 
sound ranges under various oceanographic con¬ 
ditions. Training was required for the officers- 


RESTRICTED 



4 


INTRODUCTION 


who were to use BT and, to a lesser extent, for 
technicians who were to service it. Some in¬ 
struction was given at WHOI to special groups, 
but the major emphasis was on field work. 
During 1942 and 1943, WHOI representatives 
made regular visits to training activities and 
ASW ships. In 1944, an intensive program of 
refresher instruction and manual revision was 
organized by UCDWR in collaboration with 
BuShips. BT pilot instructors traveled from 
one Navy activity to another giving instruc¬ 
tion on new BT developments. Work was started 
on a series of BT manuals which were to in¬ 
clude up-to-date information derived from 
oceanographic research. 

MAD Training. The magnetic airborne de¬ 
tector [MAD] was developed by the Airborne 
Instruments Laboratory [AIL], Mineola, and 
practically all training in the use and main¬ 
tenance of MAD was carried out by the labora¬ 
tory. It was necessary to train radio operators 
in the interpretation of MAD indications, pilots 
in methods of search and tracking, and tech¬ 
nicians in upkeep and repair. Courses for these 
three purposes were taught by laboratory per¬ 
sonnel during 1943 and 1944. A simple train¬ 
ing device was constructed to teach pilots the 
rudiments of MAD tactics and a more elaborate 
trainer, simulating MAD search and attack 
conditions, was built to give team training to 
pilots and MAD operators. 


12 SELECTION AND TRAINING OF 
SUBMARINE PERSONNEL 

By late 1943, efforts, particularly at New 
London, were being directed towards the de¬ 
velopment of equipment, principally sonar, for 
submarines. In the selection and training work 
a corresponding shift in emphasis took place. 
Only a limited amount of work was done, how¬ 
ever, on selection of submarine personnel. 
Primary concern of the Division 6 groups was 
with training. Here the background of two 
years’ experience in ASW work was a valuable 
asset; it made possible the rapid development 
of well-integrated effective training programs. 

Assistance to the submarine forces in the 


selection and training of personnel was con¬ 
tinued by Division 6 until termination of its 
activities in June 1945. After that date, several 
of the groups which had formed part of Divi¬ 
sion 6 carried on similar work under direct 
contracts with the Navy. A submarine training 
section was established at New London under a 
contract between Columbia University and the 
Bureau of Naval Personnel; a second group, 
under a University of California-BuShips con¬ 
tract, maintained assistance to WCSS; and 
WHOI, under BuShips contract, continued to 
aid in BT training. 


1-21 Selection 

For a short period during 1942, a represent¬ 
ative of Division 6 worked with the Medical 
Research Department, Submarine Base, New 
London, on sonar operator selection. On several 
later occasions, assistance was provided in the 
form of consultation on selection procedures or 
construction of special testing equipment. 

Selection of submarine sonar operators was 
considered a relatively unimportant problem. 
The sonar operator did not play the major role 
on submarines that he did on ASW surface 
craft. There were no rated sonarmen until 1945 
and then only a few. Commanding officers filled 
the sonar watches by assigning men of other 
rates who were not occupied full time. As a 
consequence, the system followed in the sub¬ 
marine schools was to give sonar operator train¬ 
ing to all men, or to as many as possible, who 
might be called upon to stand sonar watches. 
The problem then was not one of selecting the 
men best qualified to be sonar operators but 
simply one of eliminating those men who might 
be potentially dangerous because of marked de- 
ficiences of hearing, speech, or motor coordina¬ 
tion. 

From July 1944 to January 1945, a group 
from the CUDWR laboratory was stationed at 
Pearl Harbor to work with ComSubTrainPac 
on selection and training problems. Their chief 
contribution was the establishment of a system 
whereby (1) all men assigned to ComSubPac 
were classified on the basis of standard Navy 
tests, education, experience, and interest, and 


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SELECTION AND TRAINING OF ANTISUBMARINE PERSONNEL 


5 


(2) entrance standards were set for all courses 
given by ComSubTrainPac. In this way, waste 
of training facilities on unqualified men was 
largely eliminated. The work started by the 
CUDWR group was continued by a Selection 
and Training Officer added to the ComSub¬ 
TrainPac staff. 


1.2.2 rp . . 

framing 

In the ASW work, assistance had been pro¬ 
vided first in one aspect of training and then 
in another to meet new demands as they arose. 
Too often there was a lack of integration of 
efforts of several groups working on related 
problems. Profiting by the ASW experience the 
Division 6 training groups followed a more or¬ 
derly procedure in attacking submarine prob¬ 
lems. Requests for specific assistance of a lim¬ 
ited nature were sidetracked in favor of those 
for assistance in revamping or establishing en¬ 
tire programs. The development of each new 
training program included the following steps. 

1. Analysis of training requirements. 

2. Survey of existing facilities. 

3. Planning of curricula. 

4. Training of instructors. 

5. Development of achievement tests. 

6. Preparation of training aids. 

7. Construction of synthetic trainers. 

8. Field service to introduce the new pro¬ 
gram. 

Complete programs of this nature were suc¬ 
cessfully carried out for sonar, voice communi¬ 
cations, and radar training. 

Sonar Training. Submarine sonar training 
expanded rapidly during 1944 and early 1945. 
Division 6 assisted in the planning and estab¬ 
lishment (1) of new basic courses for sonar 
operators at Pearl Harbor, New London, and 
San Diego; (2) of a basic maintenance course 
at New London; and (3) of refresher courses 
for operators and maintenance men at Pearl 
Harbor, Perth, and New London. Special 
courses were established at a number of other 
submarine bases. 

Operator and maintenance training for JP 
sonar, an equipment developed by the CUDWR 
laboratory, was begun prior to the more gen¬ 


eral expansion of submarine sonar training. 
Laboratory representatives prepared training 
materials and introduced JP courses at subma¬ 
rine bases in both the Atlantic and Pacific. 
Training for other sonar equipments developed 
by Division 6 laboratories came at a later date 
and was added to existing sonar courses. Lab¬ 
oratory training groups wrote operator and 
maintenance instruction books, made record¬ 
ings, built trainers, and outlined suggested 
courses. In each instance these training mate¬ 
rials were distributed to training activities 
prior to the installation of production equip¬ 
ments on submarines. 

Voice Communications Program. In order to 
fulfill a request of ComSubsLant for assistance 
in developing voice communications training, 
Division 6 enlisted the aid of two other NDRC 
groups, namely, Psycho-Acoustic Laboratory at 
Harvard University and Project N-109 of the 
Applied Psychology Panel. The three groups 
collaborated in a twofold program which in¬ 
volved (1) standardization of phraseology and 
procedures used in voice communications and 
(2) establishment of training courses for offi¬ 
cers and men. 

Work was begun in April 1944 and concluded 
in December. By that time a catalogue of stand¬ 
ard commands and reports, an instruction book 
on basic procedures, and a ship’s organization 
chapter had been prepared and issued. Basic, 
intermediate, and advanced training courses 
had been started. Instructors had been trained 
to give the voice communication courses at ad¬ 
vanced bases, and equipment for training rooms 
had been assembled and shipped to these bases. 

Submarine Bathythermograph Program. 
Bathythermographs provided information use¬ 
ful to submarines both in predicting sound 
ranges and in diving. From early 1942 until 
termination of Division 6 work in 1945, assist¬ 
ance was given in the training of diving officers, 
sonar officers, and maintenance men. The assist¬ 
ance was chiefly of two kinds—field instruction 
and preparation of manuals. 

Representatives of the WHOI and UCDWR 
laboratories visited submarine bases in both the 
Atlantic and Pacific to assist in installation of 
equipment and to give training in its use and 
maintenance. 


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6 


INTRODUCTION 


A series of instruction books were written 
by WHOI and UCDWR, printed by BuShips, 
and distributed to all submarine activities. 

13 SUGGESTIONS 

The Division 6 groups worked for three and 
a half years on problems of selecting and train¬ 
ing Navy personnel during a wartime emer¬ 
gency. A brief summary of this work has been 
given and a more detailed account is presented 
in the chapters which follow. For the future of 
Navy selection and training tentative conclu¬ 
sions arising from the experiences of the Divi¬ 
sion 6 groups are suggested. 

131 Selection 

Under wartime conditions true selection re¬ 
search is impractical. Experimental conditions 
cannot be controlled adequately and the pres¬ 
sure to obtain positive results and to apply 
them immediately is too great. Carefully 
planned research programs should be carried 
on in time of peace so that selection plans are 
ready for immediate use if an emergency arises. 
In time of war, selection research should have 
only two aims: (1) continual verification of 
the procedures in use; (2) solution of the new 
and unexpected problems which are bound to 
arise. 

The selection of men for any particular spe¬ 
cialty, such as sonarman, should be only a 
phase of a much broader program, that is, the 
classification and assignment of all men on the 
basis of their aptitudes, experience, education, 
and interests. Only such a general program can 
make the most efficient use of available man¬ 
power and avoid the waste and confusion which 
occurs when various specialties compete for 
the best men. 

Comments on the specific selection problems 
which were encountered by Division 6 are given 
at the ends of Chapter 2 and Chapter 4. 

132 Training 

Although the Navy training programs in 
which Division 6 participated were effective, 
as evidenced by the success of the groups to 


whom training was given, there were a number 
of serious deficiencies which deserve future con¬ 
sideration. 

Operational Research. A constant handicap in 
the development of training courses was the 
lack of the particular kind of operational re¬ 
search necessary (1) to evaluate new equipment 
from the standpoint of ease in using and main¬ 
taining it and (2) to formulate new doctrines 
and procedures governing its use. 

Early in its development each new or modi¬ 
fied equipment should be given field tests to 
answer such questions as the following. How 
convenient is the arrangement of controls which 
the operator manipulates; how legible are the 
meters and dials; can controls, meters, and dials 
be rearranged so as to simplify operation; does 
the equipment cause excessive operator fatigue; 
are parts readily accessible for maintenance; 
can whole units be quickly replaced; is the de¬ 
sign such that trouble shooting can be entrusted 
to a relatively inexperienced technician; are 
there features which add excessively to operat¬ 
ing or maintenance difficulties? These and simi¬ 
lar questions are of the utmost importance when 
operators and maintenance men must be 
trained quickly. They are also important for 
the final success of the equipment under actual 
operating conditions. Answers should be 
clearly determined before the design of new 
equipment is frozen for production. 

Most innovations in equipment necessitate 
changes in operational procedures and tactics. 
Adequate new doctrines can be developed only 
through experiments under realistic field con¬ 
ditions. Neglect of this aspect of research means 
that old doctrines continue to be taught until 
the equipment has been in use for some time, or 
new doctrines are established on the basis of 
opinion rather than facts. In either case, the 
result is delay in the effective use of the new 
equipment. Two typical instances of such de¬ 
lays can be cited. BDI equipment had been in¬ 
stalled on ASW ships for several months before 
an adequate conning doctrine based on center 
bearings was established. Almost a year was 
lost before the full potentialities of the sound 
range recorder were discovered incidentally in 
the course of research on forward throwers. 

Administration. The officers placed in charge 


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SUGGESTIONS 


7 


of schools and training courses were, almost 
without exception, unfamiliar with the stand¬ 
ard methods of education and school adminis¬ 
tration which have long been accepted in civi¬ 
lian schools. It is as unfair ,to expect a Navy 
officer without special training to administer a 
school as it is to expect a superintendent of 
schools to command a ship. The frequent rota¬ 
tion of school administrators only added to the 
fundamental weakness of the system. About the 
time an officer had begun to learn something 
about his job, he was transferred and a new 
man took his place. 

An important step forward for the Navy edu¬ 
cational system would be to put the direction 
of its schools into the hands of men profes¬ 
sionally qualified as educational administrators. 
This might be accomplished in several ways. 
Selected Navy officers could be given advanced 
training in educational administration. Profes¬ 
sional educators could be commissioned as Navy 
officers. Or civilian specialists could be em¬ 
ployed as school administrators. 

Planning of Training. To be effective, trafn- 
ing courses must be planned on the basis of 
facts. How many men are needed and at what 
rate? What knowledge must they be given? 
What skills must they acquire? How long will 
it take them to gain sufficient knowledge and 
skill? How many instructors and how much 
equipment are necessary to train the number 
of men in the time allowed? These and many 
other questions must be answered as accurately 
as conditions permit. Then the course can be 
planned to accomplish the desired aims. 

Unfortunately, Navy courses were not always 
planned this way. As an example, take the 
ASW sonar operator course. It was established 
as a five-week course in the spring of 1942. 
Two years later, it was still a five^week course 
although there had been added to the operator’s 
job: operation of the sound range recorder, 
rudiments of plotting and use of BDI. In sonar 
maintenance, men with no experience or train¬ 
ing in electronics were given a ten-week course 
and expected to service elaborate electronic 
equipment. When the number of equipments 
which they might be called upon to service had 
more than doubled, the course was lengthened— 
to twelve weeks! 


Instructors. Next to the lack of trained ad¬ 
ministrators, the lack of trained instructors 
was probably the greatest weakness in the Navy 
training system. The majority of instructors 
were conscientious and hard-working, but they 
were not qualified teachers. Too often those 
who became good teachers were transferred and 
replaced by inexperienced men. Like adminis¬ 
trators, instructors should be given special 
training or selected because they have had the 
necessary training. 

Training Facilities. Classroom and laboratory 
space, standard equipment, synthetic trainers, 
and training aids should be planned to meet the 
needs of a training course. Too often the re¬ 
verse procedure is followed, i.e., the course is 
planned to suit the available facilities. 

Classroom and laboratory space should be di¬ 
vided so that students can be handled in small 
manageable groups. For the kind of training 
usually needed in Navy courses, emphasis 
should be placed on adequate provisions for 
laboratory work and operating drill rather than 
on lecture rooms. 

Standard equipment should be provided for 
training before it is delivered for Service use. 
This means that training needs must be kept in 
mind at the time production schedules are 
established. 

Synthetic trainers should be designed to meet 
the needs of a training course. It is sheer 
waste to build a trainer, however clever it may 
be, which does not fit into the training require¬ 
ments. A good synthetic trainer, in addition to 
filling definite needs in a training course, should 
have a number of other features. It should 
teach skills actually required on real gear; it 
should provide a reliable scoring system; and 
it should be reasonably rugged and easy to 
maintain. Experiments should be conducted 
with every synthetic trainer to show the value 
of practice on the trainer relative to practice 
on real equipment and to no practice at all. 

Each particular kind of training aid—in¬ 
struction book, phonograph recording, movie— 
should be used only for the purpose to which 
it is best adapted. Instruction books are ex¬ 
cellent for imparting verbal knowledge but they 
are no substitute for laboratory practice or 
operating drill. Phonograph recordings are 


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8 


INTRODUCTION 


especially valuable for teaching recognition of 
underwater sounds but they cannot take the 
place of a good lecturer. Movies can be used to 
advantage in presenting an overall picture of a 
tactical situation or in giving a general intro¬ 
duction to a new kind of device but they have 
little or no value in teaching detailed operating 
procedures. 

The persons responsible for planning of 
training facilities, design of synthetic trainers, 
and preparation of training aids should have 
an intimate knowledge of the training situation 
for which the work is being done. 

The Relation of Training to 
Research and Development 

Close liaison should be maintained between 
training activities and the laboratories engaged 
in research and development work. During the 
course of their experimental work, laboratory 
groups acquire a great deal of knowledge about 
how to use and maintain the equipment which 
they develop. This information should be 
passed on to training activities. This is of spe¬ 
cial importance during an emergency when 
every effort is being made to rush production 
and get new devices into use as quickly as pos¬ 
sible. 

The laboratories of Division 6 found it con¬ 
venient to establish training groups which 
served as intermediaries between the research 
and development groups and training activities, 
thereby relieving the former of duties such as 
writing instruction books and giving instruc¬ 
tion, and providing the latter with maximum 
assistance. Similar training groups might well 
be added to the staffs of all laboratories design¬ 
ing and developing equipment for the Navy. 

1 - 3 - 4 Overall Coordination of Selection 
and Training 

In ASW selection and training, a fair degree 
of coordination was maintained through 


COMINCH 10th Fleet and through the Bureau 
of Naval Personnel. There was, however, too 
little direct intercourse between the two main 
sound schools, and between these schools and 
other ASW activities. Procedures taught to 
operators and doctrines taught to officers were 
for long periods lacking in uniformity. Two or 
more groups often paralleled each other’s efforts 
on projects which could have been conveniently 
subdivided. Valuable innovations introduced by 
one activity remained totally unknown to the 
others. 

In submarine selection and training there 
was no analogue of ASW’s 10th Fleet to super¬ 
vise and coordinate the work of various com¬ 
mands. The lack of overall coordination was, 
therefore, more noticeable. In parts of the work 
observed by Division 6 groups there appeared to 
be little common planning by the activities re¬ 
sponsible for training in the Atlantic and in the 
Pacific, nor by the operational training com¬ 
mands and the basic schools. And there was, 
seemingly, no agency responsible for establish¬ 
ing uniform standards for entry into the sub¬ 
marine service. For example, at New London 
men were carefully screened by the Medical 
Research Department and strict physical and 
mental requirements were met. At other bases, 
however, men less well qualified were admitted, 
evidently because neither the medical nor per¬ 
sonnel departments at these bases had been di¬ 
rected to maintain the standards in effect at 
New London. 

To get the most done in the least time it is 
probably desirable to have numerous units oper¬ 
ating almost autonomously. But there is a 
danger that the units may not only work inde¬ 
pendently, they may also remain unaware of 
each other’s progress. The mistakes of one 
group may be repeated unnecessarily by others; 
or, conceivably, the efforts of one may be in 
opposition to those of another. Some central 
agency should act to coordinate and supervise 
the work of all closely related activities. 


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Chapter 2 

SELECTION OF ANTISUBMARINE WARFARE PERSONNEL 


S election research was undertaken by Divi¬ 
sion 6 for three classes of antisubmarine 
warfare [ASW] personnel: sonar operators, 
sonar maintenance men, and sonar officers. 
Work on operator selection was begun promptly 
after acceptance of the selection and training 
project by NDRC late in 1941; it was continued 
intermittently during the next two years. A less 
elaborate program of research on selection of 
sonar maintenance men was carried on during 
a period beginning in the summer of 1942 and 
ending in the spring of 1944. Both of these 
projects produced selection schemes which were 
effective in improving the quality of sonar per¬ 
sonnel. Considerable research was done on offi¬ 
cer selection during 1943 and 1944. Results did 
not show sufficient promise to warrant the 
establishment of a selection scheme for sonar 
officers. 

21 SONAR OPERATOR SELECTION 

The seriousness of antisubmarine warfare at 
the time of our entry into World War II gave 
rise to a demand for large numbers of trained 
sonar operators. The importance of the sonar 
operator’s job and the short time allowed for 
training made it essential to select men with 
the aptitudes necessary to their becoming good 
sonar operators, or at least men with the apti¬ 
tudes necessary for successful completion of 
the sonar operator training courses. Fortu¬ 
nately, large groups of men from which to draw 
were available at naval training centers. 

At the first meeting with the Navy of the 
Committee on Selection and Training, Division 6 
was asked to give immediate attention to a 
selection program. The committee visited the 
sound schools, where they observed sonar oper¬ 
ators during practice attack runs and discussed 
selection problems with the school staffs. Agree¬ 
ment was reached on the essential features of 
the operator’s job and the aptitudes required 
for it. Experimental work on selection tests 
was begun in January 1942. By March, suffi¬ 
cient results had been accumulated to warrant 
thd proposal of an initial selection scheme. The 


scheme was accepted by the Navy and put into 
immediate use at the naval training centers. By 
the end of April, candidates selected by the new 
methods were arriving at the sound schools. 

211 Initial Operator Selection Scheme 

After considering the relevant test materials 
readily available for administration to large 
groups, the committee selected the following for 
experimental use. 

1. Otis Test of Mental Ability, Higher Form 
(20 minutes). 

2. Bennett Mechanical Comprehension Test, 
Form AA. 

3. Seashore Measures of Musical Talent, 
First Edition: Pitch, Intensity, and Tonal 
Memory Tests. 

These tests and a specially constructed per¬ 
sonal history questionnaire were given as 
quickly as possible to 92 students at Key West 
and 109 at San Diego. 

Measures of operator performance available 
at the two schools were examined as criteria 
for the selection tests. It was the opinion of the 
research group that the best single criterion 
was that obtained at San Diego where two ex¬ 
perienced instructors selected the best operators 
on the basis of performance during attack 
teacher drills. In the absence of a similar meas¬ 
ure for Key West students, the final grade in 
the operator’s course was taken as the criterion 
for validation. For both experimental groups, 
students were divided into two categories, 
“better” and “others.” Many different combina¬ 
tions of tests were tried in order to determine 
the one which would best discriminate between 
the two groups. The following scheme appeared 
most promising. 

Screen I. Reject any man whose standard 
score a on the Otis Test of Mental Ability is 
below 35. 


a To make scores on all tests comparable, raw scores 
were converted to standard scores. The mean raw score 
of a large sample of the population being tested was 
assigned a standard score of 50. The standard deviation 
(a) was taken as 10. 


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9 



]0 


SELECTION OF ANTISUBMARINE WARFARE PERSONNEL 


Screen II. Average the standard score on the 
Bennett Mechanical Comprehension Test with 
the mean of the standard scores on the three 
Seashore tests (pitch, tonal memory, and in¬ 
tensity). Reject any man whose average score 
is below 45. 

Table 1. Validation of initial selection scheme.* 


San Diego (Criterion, attack teacher ratings) 

Others Better Number 


Men who passed both screens 

53% 

47% 

85 

Men who failed one or both 

100% 

0% 

24 

Key West (Criterion, final grades) 


Men who passed both screens 

38% 

62% 

39 

Men who failed one or both 

81% 

19% 

53 


♦This and following tables may be read as follows: Of 85 men 
who passed both screens at San Diego, 47% were in the group classed 
as Better on the basis of their attack teacher grades, 53% in the 
Others group. 

Applied to the experimental groups, the dual 
screen produced the results 1 shown in Table 1. 
The differences which may be noted in the two 
tables are in part due to the different criteria 
used, but also to the marked difference in qual¬ 
ity of men, which is evidenced by the percen¬ 
tages passing both test screens. At San Diego, 
78 per cent passed both screens; at Key West, 
only 42 per cent. 

Although these results were based on a lim¬ 
ited number of cases, it was felt that the urgent 
circumstances justified the immediate adoption 
of the scheme. The Bureau of Personnel con¬ 
curred, but proposed substituting the Navy 
General Classification Test [GCT] for the Otis, 
since the former was already in routine use at 
the training centers. According to the data 
then available, the passing score on the Otis 
was equivalent to a GCT score of 82, so the 
latter was adopted as the Screen I standard. 
Later it was found that the corresponding score 
was actually lower, and the passing score on 
the GCT was reduced to 76. 


2-1,2 Interim Research on Operator 
Selection 

During the period following adoption of the 
initial selection plan a considerable amount of 
effort was spent in gathering additional data 


on its validity, in checking on proper admin¬ 
istration of the tests at training centers, and 
in investigating factors which were not covered 
in the initial test battery. 

Early Follow-up Studies. At San Diego and 
Key West complete records of selection test 
scores and school grades were kept for all stu¬ 
dents, and records of interviews with failing 
students were added in the course of time. 
Since some unselected men transferred from 
sea or not properly screened at the training 
centers continued to appear in the classes, it 
was possible to check periodically on the effec¬ 
tiveness of the selection plan. In the fall of 
1942, a tabulation at San Diego showed that 
the two-screen method was discriminating sat¬ 
isfactory from unsatisfactory students (see 
Table 2). Ninety-four per cent of the men who 

Table 2. Follow-up of initial selection scheme. 

San Diego (Criterion, final grades) 

Unsatis- Satis¬ 
factory factory Number 

Men who passed both screens 6% 94% 257 
Men who failed one or both 27% 73% 168 


passed both screens were making satisfactory 
(above 3.0) grades. Twenty-seven per cent of 
the men who failed one or both screens were 
unsatisfactory. It should be noted that many 
of the men shown in the table as failing one 
or both screens were borderline cases. The num¬ 
ber of unselected or improperly selected men 
grew rapidly smaller as fewer men were trans¬ 
ferred from sea and as administration of selec¬ 
tion tests at the training centers improved. 

An effort was made in 1942 to obtain records 
of performance under service conditions. Oper¬ 
ating ships were asked to fill out standard re¬ 
port forms for graduates of the operator 
courses. The number of reports received was 
not adequate for statistical treatment. 

Meanwhile, IBM forms were provided to per¬ 
mit machine scoring of all tests administered 
at the training centers. Continued checks were 
made on test reliability and close contact was 
maintained with the training centers to make 
sure that tests were administered and scored 
properly and that only men who passed both 
screens were assigned to the schools. 


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SONAR OPERATOR SELECTION 


11 


Fleet Selection. Throughout most of 1942, the 
sound schools continued to receive a consider¬ 
able number of students from the fleet. Perhaps 
chiefly because ships tended to send the men 
they could best spare, these fleet transfers were 
decidedly inferior as students to the men se¬ 
lected at the naval training centers. Authoriza¬ 
tion was obtained, therefore, to give the selec¬ 
tion tests to all men assigned to the school from 
sources other than the training centers and to 
refuse admittance to those who were not quali¬ 
fied. 

In the meantime, a selection scheme was de¬ 
veloped which could be used aboard ship. It 
differed from that in use at the training centers 
in two respects: an Inventory of Musical Back¬ 
ground was substituted for the Seashore tests, 
and the Bennett Mechanical Comprehension test 
was treated as a separate hurdle. A manual of 
directions for administering the tests was writ¬ 
ten and was included by BuPers in packages of 
test materials distributed to ASW ships. About 
this time, however, the transfer of men from 
ships directly to the sound schools was stopped 
and the practicability of the shipboard selection 
scheme was never determined. 

Audiometer Tests. At the New London Sub¬ 
marine Base audiometer tests had been in use 
prior to 1942; at Key West and San Diego they 
were quickly instituted for all entering stu¬ 
dents. The need for such tests was soon con¬ 
firmed. Although all recruits had been given 
medical tests involving whispered voice or coin 
clicks, many cases of serious hearing loss were 
found and even occasional instances of almost 
complete deafness in one or both ears. 

Extensive studies were made of the relation 
between hearing loss and various criteria of 
school achievement. For this purpose audio- 
grams were classified according to the scheme 
described in Section 4.1.1, and the influence of 
different levels of hearing loss was systemati¬ 
cally examined. In brief, defective hearing was 
found to be significant for sonar operation if it 
involved more than a 25-db loss in the 512-2,048 
cycle region in one or both ears, or more than 
35 db at 4,096 and 8,192 in both ears. Table 3 
based upon a study made in San Diego during 
1944 2 shows the higher failing rate among men 
with significant hearing loss. 


On several occasions it was suggested that 
audiometer tests be given at the training sta¬ 
tions to eliminate men with significant loss 
before they reached the schools. This was never 
done because of the time required to test all 
candidates. However, use of the tests at the 

Table 3. Effect of significant hearing loss. 

San Diego (Criterion, final grades) 

Failed Passed Number 

Normal hearing or insignificant 

loss 8% 92% 3,823 

Significant hearing loss 15% 85% 180 


schools was continued, and men with severe 
hearing loss were dropped. 

In order to reduce the labor in giving the 
tests, an abbreviated procedure was developed 
at New London (see Section 4.1.1), and some 
preliminary work was done on a method of 
group testing. The latter was not completed 
because of the pressure of more urgent prob¬ 
lems. 

Tonal Tests. As the importance of doppler 
discrimination became more widely appreci¬ 
ated, increasing attention was devoted to the 
auditory discrimination requirements of the 
initial testing scheme. One weak feature was 
soon apparent, that is, the practice of averaging 
scores on the musical aptitude and mechanical 
comprehension tests was permitting men with 
inadequate tonal discrimination but high Ben¬ 
nett scores to slip through. This was corrected 
in the final selection scheme. 

It also appeared, from studies conducted at 
San Diego and New London, that the Seashore 
tests as they were used in the selection program 
had a number of defects. The lack of standard¬ 
ized directions on the records, the inadequate 
numbering of items, and other factors lowered 
the reliability of the tests. In addition, the in¬ 
tensity test was found to have little validity, 
the predictive value of pitch and tonal memory 
being as great as that of all three together. 

Efforts were therefore concentrated on de¬ 
veloping a single improved test which would 
measure both pitch discrimination and tonal 
memory and which would be better adapted, 
from the standpoint of ease of administration, 
for use at naval training centers. After several 


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12 


SELECTION OF ANTISUBMARINE WARFARE PERSONNEL 


months of experimental work, a Sonar Pitch- 
Memory Test was produced. 3 The new test w r as 
used in the final revision of the operator selec¬ 
tion scheme. 

Studies of Other Factors. The influence of 
age and education upon success in the sound 
school was investigated at San Diego. It was 
found that men between 20 and 33 years of age 
were superior on the average to younger and 
to older men, and that men who had completed 
11 years of school were superior to those who 
had not. These findings were never utilized, 
because the incoming recruits were predomi¬ 
nantly very young men, and an age or schooling 
requirement would have eliminated an unrea¬ 
sonably large percentage. 

Other studies showed that men who had vol¬ 
unteered for sound school obtained better 
grades than men who had not, but the difference 
became negligible when the two groups were 
equated in terms of aptitude test scores. Train¬ 
ing centers were instructed by BuPers to select 
volunteers, and did so whenever the supply of 
qualified volunteers was sufficient to meet the 
quota. To increase the number of informed vol¬ 
unteers, a pamphlet describing the sonar oper¬ 
ator’s job was prepared for distribution to can¬ 
didates at the training centers. 

Because a number of failing students com¬ 
plained of eyestrain, a study of near-vision 
acuity was carried out at San Diego (the usual 
Navy test is given only at 20 ft). Scores on the 
Snellen charts were obtained at both 18 in. and 
at 20 ft. However, the number of cases failing 
in the 18-in. test was so small that no clear-cut 
relation to operator performance could be 
established. 

No adequate tests of motor coordination were 
developed. Preliminary experiments with a two- 
hand pursuit meter and with a paper-and-pencil 
group test involving coordinated response to 
sound did not give results of sufficient promise 
to warrant additional study. Men with obvious 
motor defects were supposedly eliminated at the 
training center. 

2-1,3 Final Operator Selection Scheme 

In the fall of 1943, the naval training centers 
began using the new set of basic classification 


tests developed by BuPers. With a view to sub¬ 
stituting these tests wherever possible for those 
in the sonar operator selection battery, a new 
study was made. Scores on the following tests 
were accumulated for 245 students at San Diego 
and for 259 at Key West. 

1. GCT (NavPers 16502). 

2. Reading and Arithmetical Reasoning 
(NavPers 16512). 

3. Mechanical Aptitude (NavPers 16524). 

4. Bennett Mechanical Comprehension. 

5. Seashore Measures of Musical Talent 
(tests of time and timbre from new edition). 

6. Sonar Pitch-Memory (prepared by Divi¬ 
sion 6). 

Since the students being studied had already 
been preselected in accordance with the initial 
selection plan, validation paralleling that of the 
initial scheme was not possible. However, ex¬ 
tensive analysis was made of various test com¬ 
binations in relation to the criteria available in 
order to determine which combination gave the 
best prediction. 4 The following scheme was rec¬ 
ommended : 

Screen I. Reject any man who makes a 
standard score of less than 50 on the new GCT 
or on any two of the other three Navy tests 
(reading, mechanical aptitude, arithmetical 
reasoning). 

Screen II. Reject any man who makes a 
standard score of less than 50 (raw score of 
80) on the Sonar Pitch-Memory Test. 

Examination of these two screens will show 
that they are somewhat more rigorous than the 
corresponding parts of the initial selection plan. 
Screen I (see Table 4) adds an additional hurdle 

Table 4. Validation of Screen I, final operator 

selection scheme. 


San Diego and Key West, combined (Criterion, 
written examination average) 

Failed Passed Number 

Men who passed Screen I 10% 90% 259 

Men who failed Screen I 29% 71% 245 


to the simple requirement of a satisfactory 
GCT. Screen II eliminates the possibility of 
having a man with poor tonal discrimination 
slip through on the basis of a good mechanical 
aptitude score. The Sonar Pitch-Memory Test 


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SELECTION OF SONAR MAINTENANCE STUDENTS 


13 


had been found more reliable than the Seashore 
tests previously used, and was further sup¬ 
ported by a correlation of 0.74 with doppler test 
scores. There is every evidence that the revised 
scheme would prove to be superior to the initial 
selection scheme, if both could be validated with 
a large unselected group. 


Discussion 

The principal factors measured in both the 
initial and final selection schemes were general 
intelligence, mechanical comprehension, and 
auditory discrimination. Severe hearing loss 
and gross speech and motor defects were also 
considered. Of a number of other factors which 
are undoubtedly important in operation of 
sonar equipment, several were the subject of 
preliminary study; others were completely 
neglected. All would bear investigation in a 
peacetime research program. 

Eye-Ear-Hand Coordination. Marked individ¬ 
ual differences were apparent in the ability to 
make appropriate movements to a complex of 
visual and auditory signals. Tests which were 
tried in an attempt to measure aptitude for 
acquiring this sort of skill were probably over¬ 
simplified. Further study should be made to 
compare the effectiveness of batteries of specific 
tests and a single job-sample type of test. Re¬ 
search should also include a careful study of 
the effect of practice. To what extent can the 
lack of aptitude be overcome by drill? 

Temperament. This is perhaps the most im¬ 
portant characteristic of all but also the most 
difficult to measure. It received practically no 
study in the program here described. Personal 
history questionnaires were administered but 
there were no criteria against which to validate 
the results. Research is needed to develop tests 
which will select the man who will do his job 
conscientiously day after day, who will not suc¬ 
cumb to monotony, and who will not go to pieces 
under stress and excitement. 

Visual Imagination. A Relative Movement 
Test, designed primarily to measure ability to 
visualize relative position and movements of 
own ship and target, was never applied to sonar 
operator selection because of the lack of good 


performance criteria for its validation. This 
ability is sufficiently important, for operators as 
well as officers, to justify further study. 

Auditory Tests. Besides the pitch-memory 
test which had face-validity as a measure of 
ability to make doppler judgments, other tests 
of auditory discrimination might well be ex¬ 
amined. It would seem particularly important 
to devise a test which measures ability to de¬ 
tect a weak signal in a background of noise. 

Unless other auditory tests are used which 
eliminate the man with gross hearing loss, 
further attention needs to be given to the de¬ 
velopment of an audiometer suitable for group 
testing. Such an instrument would have more 
general value than merely testing of sonar 
operators. 

Visual Tests. The increased use of the cath¬ 
ode-ray screen to give a picture of the sounds 
heard adds emphasis to the importance of good 
near-vision. Visual problems such as reading 
of dials should be overcome by proper equip¬ 
ment design. 

As already noted, the selection researcher 
must know to what extent and at what rate nec¬ 
essary skills can be acquired by practice. Em¬ 
phasis should be placed on developing measures 
of aptitude for the skills which are least sus¬ 
ceptible to practice. 

The problem of good performance criteria is 
also fundamental to selection research. Ideally, 
the best criterion would be an accurate measure 
of total performance under actual operating 
conditions. Practically, such a measure is usu¬ 
ally impossible to obtain. In the selection of 
sonar operators, and for that matter in the 
selection of most specialized personnel in the 
Navy, the first aim is to select men who can 
successfully pass a training course. If this pre¬ 
diction of competency is to carry over to per¬ 
formance on the job, a constant effort must be 
made to make measures of achievement in train¬ 
ing courses realistic and reliable. 


2 2 SELECTION OF SONAR MAINTENANCE 
STUDENTS 

An elementary sonar maintenance course, ten 
weeks in length, was given at each of the sound 


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14 


SELECTION OF ANTISUBMARINE WARFARE PERSONNEL 


schools. At both schools, the first six weeks were 
devoted to simple mathematics, rudiments of 
radio theory, use of tools, and methods of mak¬ 
ing routine tests with standard test equipment. 
The final four weeks were spent in practical 
study of the maintenance and servicing prob¬ 
lems commonly encountered aboard ship. 

Students for the course were taken from the 
graduates of the sonar operator course. Since 
only a small percentage of the operator gradu¬ 
ates could be given the additional training, the 
problem was to select those who were most 
likely to do well in the maintenance course. 
Prior to the work on special selection pro¬ 
cedures, volunteers with the highest standing 
in the operator course had been chosen, but this 
method had not proved completely satisfactory. 

The selection of maintenance men differed 
from that of sonar operators in that there was 
no formal unified program. Selection methods 
were developed independently by the resident 
psychologists at the two schools. However, simi¬ 
lar results were achieved. 

Research at San Diego 

Study of the problem of improving selection 
methods for maintenance men was begun in 
the summer of 1942. Scores on standard Navy 
tests and personal history data, both of which 
were available in the men’s Service records, 
were correlated with final grades in the main¬ 
tenance course. The final grade was a composite 
of marks on weekly written examinations and 
grades given on shop work, with the examina¬ 
tion marks weighted more heavily. The reliabil¬ 
ity of the written examination average, as 
measured by odd versus even weeks, was quite 
high (0.83 for a group of seven classes). 

Initial Selection Plan. The outcome of a brief 
preliminary study was the adoption of a pro¬ 
cedure which selected men on the basis of the 
following four measures. 

1. GCT (old edition). 

2. Arithmetic Test (old edition). 

3. Number of units of education in science 
and mathematics. (One-half year in college was 
considered equal to one year in high school.) 

4. Average grade on two examinations given 
in the sonar operator course. 


All scores were converted to standard scores. 
A composite score was determined for each man 
by averaging his standard scores for the four 
measures. Correlations between the composite 
scores and final grades in the maintenance 
course ranged from 0.65 to 0.88 for a series of 
classes, whereas operator course grades alone 
gave a maximum correlation of only 0.53. 

More concrete evidence of the effectiveness 
of the plan is shown by the results in Table 5. 
A minimum passing score of 55 gave a sharp 
division between satisfactory and unsatisfac¬ 
tory students. Eighty-one per cent of the stu- 

Table 5. Validation of initial maintenance 
selection. 

San Diego (Criterion, final grades) 

Unsatis- Satis¬ 
factory factory Number 


Average standard score of 

55 or better 19% 81% 36 

Average standard score of 

less than 55 77% 23% 30 


dents with scores of 55 or better received 
satisfactory grades in the course. Seventy-seven 
per cent of students with scores less than 55 
received unsatisfactory grades. 

Revised Plan. In the fall of 1943, the basic 
battery of Navy tests given at the training sta¬ 
tions was revised. This necessitated a slight 
change in the scheme used for selecting main¬ 
tenance students, the new tests being substi¬ 
tuted for those formerly used. The new scheme 
included: 

1. GCT (NavPers 16524). 

2. Arithmetical Reasoning Test (NavPers 
16512). 

3. Reading Test (NavPers 16524). 

4. Bennett Mechanical Comprehension Test. 

5. Number of units of education in science 
and mathematics. 

6. Average grade on two operator examina¬ 
tions. 

As before, those graduates of the operator 
course were selected who had the highest com¬ 
posite scores determined by averaging the 
standard scores for the six selection measures. 

During the spring of 1944, correlations of 
composite scores against final maintenance 


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SELECTION OF SONAR MAINTENANCE STUDENTS 


15 


course grades were made for a total of 140 
students. Although these students had already 
been preselected, a small positive correlation of 
0.41 was obtained. Application of standard 
statistical procedures indicated that a correla¬ 
tion of about 0.70 would have been obtained 
with an unselected group of operator graduates. 


Research at Key West 

The first work on selection of sonar main¬ 
tenance men at Key West was begun in July 
1942. As at San Diego, scores on standard Navy 
tests and personal history data were utilized. 
Different combinations of test scores and scores 
arbitrarily assigned to such factors as educa¬ 
tion, experience, and interest were correlated 
with final grades in the maintenance course. 

Initial Selection Plan. As a result of prelimi¬ 
nary studies, a selection scheme was evolved 
and put into use in the fall of 1942. 5 It involved 
three successive hurdles. 

Screen I. Select only those men who are 
volunteers and who are high school graduates. 

Screen II. Select the men with highest 
scores on GCT, Bennett Mechanical Compre¬ 
hension Test, and Navy Arithmetical Reason¬ 
ing Test. Also consider such factors as interest 
in radio and training in electronics. 

Screen III. Select men with highest stand¬ 
ing in sonar operator course. 

The high school graduate qualification of 
Screen I had to be modified at times in order 
to fill the course quota. No specific weights were 
assigned to the several factors listed in Screen 
II. Tests were considered in the order listed, 
GCT as most important, and so on. Screen III 
was included primarily as a means of raising 
morale in the operator course, admittance to 
maintenance training being highly desired by 
the majority of the operator students. 

The effectiveness of this initial selection 
scheme is illustrated by the figures 6 in Table 6. 
These figures were compiled for a number of 
classes entering the course after the adoption 
of the selection plan. For various reasons, how¬ 
ever, a number of men had been admitted to 
these classes who did not meet the selection 
standards. 


Table 6. Validation of initial maintenance 
selection. 


Key West (Criterion, final grades) 

Unsatis- Satis¬ 
factory factory Number 

Men meeting selection standards 8% 92% 186 

Men below selection standards 22% 78% 18 


Revised Plan. When the Navy basic test bat¬ 
tery was revised by BuPers in the fall of 1943, 
Screen II of the initial plan could no longer be 
employed. It was decided to try out a new test, 
the Iowa Engineering and Physical Science 
Aptitude Test. This test included six parts: 
(1) mathematical comprehension, (2) ability 
to formulate solutions, (3) scientific compre¬ 
hension, (4) arithmetical reasoning, (5) verbal 
comprehension, (6) mechanical comprehension. 

Analysis based on 101 students showed that 
the first and fourth parts did not contribute to 
prediction of success in the course. For the 
remaining four parts, a multiple correlation of 
0.61 with final course grades was obtained. This 
multiple would have been higher but for the 
exclusion of 20 failures for whom no final 
grades were available. Using a weighted com¬ 
posite score, clean-cut discrimination was ob¬ 
tained between satisfactory and unsatisfactory 
students. Results for a total of 121 cases are 
shown in Table 7. 

Table 7. Validation of Iowa Engineering and 

Physical Science Aptitude Test. 

Key West (Criterion, final grades in 
maintenance course) 

Unsatis- Satis¬ 
factory factory Number 

Men passing Iowa test 23% 77% 86 

Men failing Iowa test 71% 29% 35 


Thereafter, the scores on the Iowa test were 
used as Screen II; Screens I and III remained 
the same. 


223 Discussion 

The available evidence indicates that a fair 
degree of success was achieved in the selection 


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16 


SELECTION OF ANTISUBMARINE WARFARE PERSONNEL 


of maintenance students. Whether the selection 
methods picked men who were most likely to 
become good shipboard maintenance men is 
not known. The criteria were heavily weighted 
with written examinations, and a major portion 
of the courses consisted of theory. In general, 
grades on written examinations and knowledge 
of theory have not been shown to be highly cor¬ 
related with actual servicing ability. A selection 
method which predicts the former successfully 
may have little value for the latter. 

At various times it was suggested that either 
the nature or the length of the maintenance 
course should be changed. Industrial concerns 
have had success in teaching relatively short 
maintenance courses which concentrate on 
standardized procedures with a minimum of 
theory. The students entering the maintenance 
courses had little or no background in elec¬ 
tronics. The attempt to teach them basic theory 
and routine maintenance procedures all in ten 
weeks did not seem wise. However, the course 
length had been established, and the Navy was 
committed to a policy of teaching maintenance 
men to be independent of the sort of fixed rou¬ 
tine procedures which are usual in industry. 


2 3 SONAR OFFICER SELECTION 

By the spring of 1943 the importance of the 
sonar officer’s job had increased to the point 
where the sound schools at Key West and San 
Diego felt that students for their sonar officer 
courses should be specially selected. Most of 
these officers were being assigned directly from 
ships, although part of the Key West students 
were sent from the Submarine Chaser Training 
Center [SCTC], Miami, and the Antisubmarine 
Warfare Instructor School, Boston. 

As a temporary measure, BuPers directed 
officer indoctrination centers to use the sonar 
operator selection scheme in choosing officers to 
be sent to sonar school. In May 1943, Division 6 
was asked to undertake a research program on 
sonar officer selection. Work was continued until 
June 1944. Because a great many unforeseen 
difficulties were encountered, no conclusive re¬ 
sults were obtained. 


2,3,1 Preliminary Research 

A battery of 13 tests, chosen by the Commit¬ 
tee on Selection and Training, was administered 
to four classes at Key West and six at San 
Diego, a total of 148 officers. Test scores were 
correlated with final grades, which were based 
upon written examinations and ratings of per¬ 
formance during attack teacher and training 
ship exercises. 

The correlations were low. The best scheme 
gave a multiple correlation of only 0.49. It 
made use of these five tests. 

1. Mathematical Comprehension and Inter¬ 
pretation Test (devised by a member of the 
committee). 

2. Bennett Mechanical Comprehension Test. 

3. Seashore Measures of Musical Talent, old 
edition (average of standard scores for pitch 
and tonal memory). 

4. Officer Qualification Test. 

5. Army Air Force Aptitude Test III. 

To check these findings, similar data were ac¬ 
cumulated for an additional 83 officers. For 31 
cases at San Diego, the multiple correlation 
dropped to 0.43; for 52 cases at Key West, al¬ 
most to zero. 7 

Certain causes for the failure were clearly 
apparent. The test battery had required nine 
hours, which had to be taken from the small 
amount of free time which students were al¬ 
lowed. Some of the tests included items which 
appeared nonsensical to the students. The 
grades used as criteria were unreliable and 
variable in standard of severity from class to 
class. Finally, just before the research started, 
the system of obtaining sonar officer students 
was changed so that the majority were drawn 
from SCTC, Miami. Since SCTC chose these 
officers on the basis of operator selection tests, 
interest, and other factors judged as relevant, 
the groups used in the validation study were 
not typical of the general officer population. 

Final Officer Research 

A second attempt to develop a suitable sonar 
officer selection scheme was made in the spring 
of 1944. By this time better criteria had become 
available. Objective-type written examinations 


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SONAR OFFICER SELECTION 


17 


of established reliability and realistic and re¬ 
liable measures of performance on the sound 
range recorder, a most important aspect of the 
sonar officer’s job, were in use at both schools. 
These two factors were combined with an in¬ 
structor’s overall rating to give a composite 
criterion. Scores on a recorder doppler test were 
used as an independent criterion. 

The test battery was also altered. Army Air 
Forces tests of surface development and me¬ 
chanical relations were revised into a more 
suitable form. A new relative movement test 
was constructed as a measure of ability to 
visualize relative position and relative move¬ 
ment of ships. (See page 18 for detailed de¬ 
scription.) The complete experimental battery, 
including these tests and some of those used in 
earlier officer and operator studies, is listed 
below. 

1. Officer Qualification Test. 

2. Relative Movement Test. 

3. Mathematical Comprehension and Inter¬ 
pretation Test. 

4. Bennett Mechanical Comprehension Test. 

5. Mechanical Relations Test (Air Force VI). 

6. Surface Development Test (Air Force 
III). 

7. Sonar Pitch-Memory Test. 

8. Seashore Time and Timbre Tests. 

The battery of tests was administered to 104 
officers at Key West and to 99 at San Diego. 8 
For the Key West group, the highest correla¬ 
tion between any single test and the composite 
criterion was 0.19. Therefore, no multiple cor¬ 
relations were determined. For the San Diego 
group, a weighted average of the Relative Move¬ 
ment and Bennett Mechanical Comprehension 
correlated 0.50 with the composite criterion. 
The Sonar Pitch-Memory Test correlated 0.72 
with scores on the doppler tests. 

The difference in results for the two schools 
was probably due mainly to the difference in 
grading systems used. It was the opinion of the 
research group that the Key West grades were 
not sufficiently reliable to be useful for a vali¬ 
dation study. 

A four-hurdle scheme using the tests which 
appeared most promising in final work at San 
Diego was suggested to BuPers as a possible 
stopgap measure. The four hurdles were these: 


1. Informed volunteer status. 

2. Relative Movement Test, raw score of 20 
or better. 

3. Bennett Mechanical Comprehension Test 
(15 min), raw score of 40 or better. 

4. Sonar Pitch-Memory Test, raw score of 
80 or better. 

Since the demand for sonar officers was by then 
decreasing and since a very high percentage of 
the officers who could be assigned to sonar 
training would have been eliminated by the 
four-hurdle scheme, it was not adopted. 

Continuation of the research program in the 
hope of obtaining a better selection scheme did 
not appear desirable for a number of reasons. 
Under existing conditions, careful administra¬ 
tion of a battery of tests was extremely diffi¬ 
cult and the lack of meaningful and reliable 
criteria could not be corrected readily. Further¬ 
more, the research group was needed to assist 
in the more urgent selection and training work 
for submarine personnel. 

About the only positive outcome of the offi¬ 
cer selection research was the development of 
the relative movement test. 9 This appeared to 
have promise as a measure of ability to visualize 
position and movement of objects in space. It 
was used by BuPers in further selection re¬ 
search. 

THE SONAR PITCH-MEMORY TEST 

The Sonar Pitch-Memory Test consists of 100 items, 
each comprising two very short tones three seconds 
apart. Subjects are required to judge whether the second 
tone is higher or lower in pitch than the first. The fre¬ 
quency of the first tone is one of three values, varied in 
random order, 775, 800, or 825 c. In each item the second 
tone differs from the first by from 5 to 35 c. The number 
of items involving each degree of difference are: 20 
items each at 5, 10, 15, and 20 c; 10 items at 25 c; 
and 5 items each at 30 and 35 c. These proportions 
were based on observed difficulty levels. Announcements 
of the serial numbers of test items and directions for 
taking the test are given on the recordings. 

In standardizing the test, the following data were 
obtained concerning score distributions and reliability. 



Num¬ 


Standard 

Devia¬ 


Group 

ber 

Mean 

tion 

Reliability 

Unselected recruits 

609 

74.2 

13.9 

0.89 (split- 
half) 

Recruits over 50 GCT 

224 

80.2 

10.6 

0.91 (split- 
half) 

Selected sonar students 

162 

88.2 

6.7 

0.84 (test- 
retest) 


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18 


SELECTION OF ANTISUBMARINE WARFARE PERSONNEL 


The test is now distributed by the Bureau of Naval 
Personnel. Records are listed as NavPers 11750 RA and 
RB and 11751 RA and RB. 

THE RELATIVE MOVEMENT TEST 

The Relative Movement Test is a test of ability to 
visualize navigational relationships. It contains 40 
questions which must be answered within 30 minutes 
without the use of sketches or diagrams. Typical items 
are 

Ship A is steering north at 10 knots. Ship B is 10 
miles west and steering northeast at 10 knots. 
Ship B will 

(a) collide with A (b) pass ahead of A (c) pass 
astern of A. 

Ship A is headed east at 10 knots when ship B 
leaves the same place headed south at 20 knots. 
After a half-hour, ship B changes course and heads 
east. After another half-hour, what is the direction 
of B from A? 


(a) SW (b) S (c) SE (d) E. 

Scores obtained from 102 officer students yielded a 
mean of 21.67 items correct, with a range from 4 to 
40 and a standard deviation of 6.11. Estimation of re¬ 
liability by the Kuder-Richardson method gave a value 
of 0.73. Some of the correlations found with other 
tests were 

Officer Qualification Test 0.26 

Sonar Pitch-Memory Test 0.28 

Bennett Mechanical Comprehension 

Test (BB) 0.41 

The first form of the Relative Movement Test was 

prepared at Key West in July 1943. It was revised and 

improved at San Diego in January 1944. The revised 
form, then designated as Form B, is the one described 
above. A further version containing 45 items was issued 
later by the Bureau of Navy Personnel as part of the 
CIC Aptitude Test (NavPers 16980) and also as a 
separate test (NavPers 16616). 


RESTRICTED 



Chapter 3 

TRAINING OF ANTISUBMARINE WARFARE PERSONNEL 


31 INTRODUCTION 

I N the fall of 1941, sonar training on a lim¬ 
ited scale was being conducted at the West 
Coast Sound School [WCSS], San Diego, and 
at the Fleet Sound School [FSS], Key West. 
The combined monthly output of the schools 
was approximately 100 operators, 30 mainte¬ 
nance men, and 20 officers. 

Then came our entry into the war and the 
sudden need for vast expansion of the anti¬ 
submarine warfare [ASW] training program. 
The number of sonar students was tripled but 
the schools had neither the facilities nor the 
personnel to train men at the rate required. 
In fact, many of their instructors and some of 
their training ships had been withdrawn for 
active duty. 

As a result, students in the greatly enlarged 
classes spent most of their time listening to 
lectures, studying the meager instruction books, 
or standing by waiting for a turn on the few 
pieces of training equipment which were avail¬ 
able. Throughout his entire course, each oper¬ 
ator received perhaps an hour or less of actual 
practice in operating standard gear. Mainte¬ 
nance students likewise had little opportunity 
to work with real equipment. Officers were given 
about the same training as the enlisted opera¬ 
tors. A few were also put through an intensive 
materiel course, with little consideration to the 
adequacy of their background knowledge or 
experience. 

There were other problems besides those 
arising from sudden expansion. Operating pro¬ 
cedures and antisubmarine attack doctrine were 
imperfectly developed and completely unstand¬ 
ardized. Few officers had received any training 
in conning a sonar attack. The morale of men 
assigned to schools for sonar instruction was 
low, because there was no sonar rating and 
therefore no chance for advancement through 
specialization in this field. Sonar students were 
frequently chosen from those least skilled and 
least ambitious. 

Such was the situation when NDRC was 


asked to assist in development of training 
methods. Although the major concern at the 
start was the development of selection meth¬ 
ods, the division also gave immediate attention 
to the problem of training sonar operators and 
maintenance men. 

Early in 1942 a group was organized at the 
University of California Division of War Re¬ 
search [UCDWR] laboratory to design syn¬ 
thetic trainers. Within a few months, primary 
and advanced bearing teachers had been de¬ 
veloped and preliminary models furnished to 
the schools while additional units were being 
manufactured in quantity. Shortly thereafter 
practice targets were developed to aid in under¬ 
way training. 

By the summer of 1942, training groups were 
in residence at both sound schools and were 
working with the instructional staffs to im¬ 
prove the training courses. Qualified civilian 
instructors had been recruited to supplement 
Navy personnel in staffing the maintenance 
schools. Meanwhile, sonar ratings had been 
established by the Navy, with a resulting im¬ 
provement in the morale of the enlisted stu¬ 
dents. 

By the end of 1942 the sound schools were 
graduating approximately 500 sonar operators 
a month. Yet the supply of synthetic trainers 
and the facilities for the sea-training phase had 
increased to such an extent that every student 
received approximately fifteen times as much 
operating practice as at the beginning of the 
year. Attack doctrines were being standardized, 
and the need for special sonar officer training 
was becoming increasingly apparent. 

During 1943 new members were added to 
the groups stationed at the sound schools and 
the scope of their work was greatly expanded. 
More attention was given to basic educational 
procedures, such as course planning, prepara¬ 
tion of instructional material, improvement of 
teaching techniques, and measurement of stu¬ 
dent proficiency. Synthetic trainers became 
available to the schools in quantity, making pos¬ 
sible a large increase in the amount of time 


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19 


20 


TRAINING OF ANTISUBMARINE WARFARE PERSONNEL 


which could be spent in operating drill. Pro¬ 
duction units of standard sonar equipment also 
became more plentiful for use in both operator 
and materiel courses. 

The work of the synthetic trainer group at 
UCDWR was supplemented by similar groups 
at other division laboratories. The pressure to 
produce devices in a hurry had been reduced 
sufficiently to permit more careful planning 
and design. Experience had shown the need for 
group training devices. With the development of 
the range recorder teacher [QFL], and the ex¬ 
periments in monitoring a number of advanced 
bearing teachers from a central console, a new 
trend toward group trainers was definitely es¬ 
tablished. 

To a limited extent, Division 6 assistance was 
extended during 1943 to ASW training activi¬ 
ties other than the two sound schools. Men 
were assigned to COTCLant and to COMINCH 
10th Fleet to advise on matters of training and 
to maintain liaison between these activities and 
the division laboratories and training groups. 

Still another extension of training activities 
arose from the need for setting up training 
programs for new ASW devices developed by 
the division laboratories. During 1943 groups 
were formed at the laboratories specifically to 
assist Navy training activities in teaching men 
to use and service this new equipment. 

By 1944 a shift in emphasis from antisub¬ 
marine to prosubmarine training was taking 
place, but considerable ASW work continued. 
The training groups at the sound schools con¬ 
centrated mainly on the introduction of new 
synthetic trainers and upon refinements in the 
methods of measuring student performance. 
Liaison work with refresher activities of the 
Atlantic and Pacific training commands was 
extended during the early part of the year. 
New synthetic trainers for group training were 
developed, notably the echo recognition group 
trainer [ERGT] and the group operator trainer. 
A number of training programs for labora¬ 
tory developments such as the hearing deviation 
indicator [BDI], the magnetic airborne detec¬ 
tor [MAD], and the expendable radio sono 
buoy [ERSB] were under way. 

Early in 1944, in collaboration with BuShips, 
a project (NS-252) was set up under UCDWR 


to write instruction books on installation and 
maintenance of all standard sonar equipments. 
A staff of some 50 persons including technical 
writers, editors, engineers, artists, and clerical 
assistants was formed. Several manuals were 
completed in 1944, the remainder in 1945. 

By 1945 ASW training was low in priority of 
importance, and the efforts of the Division 6 
training groups were being devoted almost en¬ 
tirely to submarine training. 

So much for the general historical perspec¬ 
tive. For a more detailed picture of the indi¬ 
vidual phases of ASW training, it is convenient 
to consider the work under three headings: 
(1) assistance to the Navy sound schools; (2) 
liaison; (3) training programs in connection 
with laboratory developments. 


3 2 ASSISTANCE TO THE NAVY SOUND 
SCHOOLS 

As previously mentioned, training groups as¬ 
signed to WCSS and to FSS worked closely 
with the instructional staffs at these schools 
to improve the training programs for sonar 
operators, maintenance men, and officers. As¬ 
sistance given included (1) curriculum revision, 
(2) achievement testing, (3) instructor train¬ 
ing, (4) preparation of training aids, and (5) 
construction of synthetic trainers. In some in¬ 
stances, members of the training group served 
as instructors for limited periods. 


Curriculum Revision 

As soon as training group personnel became 
familiar with the jobs of sonar operation and 
maintenance and with the procedures of the 
schools, they were able to suggest valuable 
changes or additions to the course curricula. 
Further changes became necessary as experi¬ 
ence developed. Schedules were revised to allow 
for drill periods on new synthetic trainers, and 
provisions were made for training on new 
ASW devices. In some cases, results on achieve¬ 
ment tests uncovered deficiencies which could 
be corrected only by a redistribution of time. 

At Key West, the training group aided in 


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21 


making complete revisions of curricula for op¬ 
erators, maintenance men, and officers. This 
work was started in the summer of 1942 and 
continued over the next two years. At San 
Diego, the training group never undertook a 
complete revamping of course curricula, but 
through day-to-day contacts it exercised con¬ 
siderable influence on the changes which were 
made. At both schools, training group person¬ 
nel took a particularly active part in introduc¬ 
ing instruction on new equipment and in 
developing programs for synthetic trainers. 


Achievement Testing 

At the start, the only measures of achieve¬ 
ment at the sound schools were marks on 
unstandardized written quizzes and rather per¬ 
functory ratings of performance during attack 
teacher drills ashore and simulated attack runs 
at sea. The inadequacy of these measures was 
a serious handicap in both selection and train¬ 
ing. In selection, good measures of perform¬ 
ance were needed as criteria for selection tests; 
in training, for evaluating the effectiveness of 
various aspects of the training program. A 
constant effort was therefore made to improve 
methods of measuring both technical knowledge 
and operating skill. 


1. Own ship is on course 315. Contact is made with a 
target at 015 True. Own ship then changes course to 
045. The target’s relative bearing will shift to 

1 060 

2 270 

3 285 

4 330 

2. A range of 2,000 yards is reported as 

1 Two oh double oh 

2 two thousand 

3 Two zero zero zero 

4 Two oh oh oh 

3. During search the filters should be set on 

1 Broad—Peak 

2 Broad—Flat 

3 Sharp—Band 

4 Sharp—Peak 


Figure 1. Sample questions from an objective- 
type operator examination. 

Written Examinations. Beginning in 1942, 
objective written examinations (see Figure 1) 


were substituted for the nonstandardized essay- 
type quizzes at both sound schools. During the 
next two years the quality of these standard 
examinations was constantly improved. Con¬ 
tinual review kept the subject matter in step 
with new developments in equipment, pro¬ 
cedures, and tactics. Item analysis was used to 
eliminate ambiguous and nondiscriminating 
questions. Two or more equivalent forms were 
developed for each examination. 

Unfortunately, the value of a written ex¬ 
amination as a criterion of achievement for a 
sonar operator, maintenance man, or officer is 
somewhat limited. Knowing all the answers is 
no proof that a man possesses the skills neces¬ 
sary for the job. For this reason, written ex¬ 
amination grades were finally dropped in 
computing students’ final grades at Key West, 
and were reduced to a nominal third of the 
total at San Diego. Nevertheless, written ex¬ 
aminations continued to be of value in showing 
what technical knowledge the students were 
acquiring from the lecture sessions and study 
of manuals. 

Measures of Performance. It is a routine task 
to develop good standardized written examina¬ 
tions which adequately test technical knowl¬ 
edge. It is much more difficult to find satisfac¬ 
tory measures of operating skill, especially in 
such a complex performance as that of the 
sonar operator. Yet this matter of performance 
is fundamental in validating selection methods 
or in determining the effectiveness of training. 

There were two situations in the sound 
schools where attempts to measure perform¬ 
ance could be made: (1) practice attack runs 
at sea and (2) drills on synthetic trainers 
ashore. 

Repeated efforts were made to develop re¬ 
liable measures of performance during the sea 
phase of training, but with little success, be¬ 
cause of the impossibility of obtaining uniform 
conditions for testing. Especially when sound 
conditions were bad, contacts were made at 
such short range that normal operations were 
impossible. Even with good sound conditions, 
practice attack runs could not be standardized. 

On the attack teacher, standardized runs 
could be used and students observed under com¬ 
parable conditions. A number of simple direct 


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TRAINING OF ANTISUBMARINE WARFARE PERSONNEL 


scoring methods were tried. For example, at 
Key West a scheme of counting the total num¬ 
ber of items of correct information was given 
a thorough tryout. Although this produced 
reasonably reliable scores, the method was 
dropped because it was considered too artificial. 
The best operator is not the one who pours 
out the greatest flood of information, but the 
one who makes the most skillful use of his equip¬ 
ment to produce the information needed for a 
successful attack. 

On other synthetic trainers, simple direct 
scores were more meaningful. The average 
firing time error on the range recorder teacher, 
for instance, measures the final outcome of a 
complex performance. As an indication of abil¬ 
ity in making sound discriminations, the highly 
reliable scores obtained on the standard dop- 
pler tests and later on the echo recognition 
group trainer are related to a significant part 
of the operator’s task. 

The use of scores such as these in validating 
selection procedures has been described in 
Chapter 2. They were also useful in evaluating 
the results of training. For example, the extent 
to which students were benefiting from special¬ 
ized doppler drills was measured by the doppler 
tests. Similarly, the minimum time needed to 
reach a reasonable degree of proficiency and 
the value of continued training beyond the 
minimum could be determined by use of QFL 
firing time tests (see Figure 2). 

Where there were no means of obtaining 
direct scores to indicate proficiency, checking 
systems were devised. These usually contained 
items of two different types: (1) checkoff items 
of an all-or-none nature (e.g., Operator throws 

heterodyne switch to ON position: Yes- 

No-) ; and (2) rating scale items where 

the instructor or checker was required to judge 
the degree of goodness of performance (e.g., 
Operator reports doppler: promptly and cor¬ 
rectly-, correctly but with delay-, 

incorrectly-, not at all-). 

During 1942 and 1943, a checking system 
was developed for use in attack teacher drills 
at Key West. Later a similar system was em¬ 
ployed at San Diego. At .both schools, checking 
systems were used to grade performance on 
the advanced bearing teachers and the group 


operator trainers. In some instances, weights 
were assigned to each item checked and a total 
numerical score determined. Scores determined 
in such a manner for attack teacher drills at 
Key West were found to have a reliability as 
high as 0.82 when grading was carried out by 
a trained team. 

3-2 3 Instructor Training 

Relatively little was attempted at the two 
sound schools in the way of formal classes on 
the subject of how to teach. Much was accom¬ 
plished indirectly. Navy instructors frequently 
came to members of the training group for ad¬ 
vice, and meetings to discuss new devices and 
new methods gave an opportunity to bring out 
general principles of effective teaching. 

At San Diego during 1944, phonograph re¬ 
cordings were made of the lectures of all in¬ 
structors. Training group personnel went over 
the recordings with each instructor individually 
and discussed means of improving both the 
content of the lectures and the manner of 
presentation. 

Much of the instructor training centered 
around the introduction of new laboratory de¬ 
velopments and new training devices. Special¬ 
ists from the laboratories frequently conducted 
brief training courses on new developments for 
the benefit of instructors. With new training 
devices, the original programs of instruction 
were usually developed by members of the 
training group; Navy instructors were then 
trained to take over. For example, the program 
of range recorder teacher drills at San Diego 
was worked out experimentally during late 
1943 and early 1944 by training group per¬ 
sonnel, 10 and in the spring of 1944 a similar 
method of development was used with the echo 
recognition group trainer. In each case, Navy 
instructors worked with the civilian instructors 
for several weeks before assuming full respon¬ 
sibility for conduct of the drills. 

3.2.4 Preparation of Training Aids 

Instructional materials were needed for many 
phases of the training work. From the summer 


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23 



MO 11-20 21-40 41-60 61-80 


TRIALS-► 



1-10 11*20 21-40 41-60 61-80 

TRIALS —► 



1-10 11-20 21-40 41-60 61-80 

TRIALS—► 



1-10 11-20 21-40 41-60 61-80 

TRIALS—► 


Figure 2. Effects of training on results in 


Type 1. Problems of this kind are quickly mastered. 
There is no point in long-continued training. 


Type 2. Improvement is very slow at first but finally 
takes place suddenly. Training should be continued long 
enough to take advantage of the marked increase in 
learning. 


Type 3. Improvement is continuous throughout entire 
period. Results achieved are directly proportional to 
length of training. 


Type U' There is no apparent improvement. Either 
practice time must be extended or more effective drills 
must be designed. 


different types of QFL firing drill exercises. 


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TRAINING OF ANTISUBMARINE WARFARE PERSONNEL 


of 1942 on, considerable time and effort went 
into the production of instruction books, phono¬ 
graph recordings, slides and films, and mis¬ 
cellaneous classroom demonstration devices. 

In preparing instruction books, an attempt 
was made to get away from the dull, drab, 
disorganized texts which were in use at the 
start of the war. In books for operators, useless 
technical information was eliminated; in books 
for maintenance men, such information was 
made as simple and clear as possible. Illustra¬ 
tions were used for functional, not decorative, 
purposes. 

The majority of instruction books prepared 
by Division 6 groups were for use with sonar 
equipment or synthetic trainers developed by 
the division laboratories. In a number of in¬ 
stances, however, texts of a more general nature 
were written. Assistance was given to WCSS 
in the preparation of a series of books on 
maintenance of surface craft sonar equipment. 
The first book, Notes on Servicing Radio and 
Sound Equipment, was distributed by BuShips 
in 1942. It was a revision and amplification of 
the maintenance instructions in use at the San 
Diego school. A more extensive Sonar Material 
Handbook, covering types of sound equipment, 
servicing procedures, and routine maintenance 
and adjustments, was issued in February 1943 
and similarly distributed. Later a monthly 
Sonar Bulletin giving information on new de¬ 
velopments, and a Sonar History Record (later 
called Sonar Equipment Log) were issued. 
Meanwhile, a massive 1,066-page looseleaf 
Sonar Maintenance Handbook (see Figure 3) 
was in process of preparation. It was issued in 
August 1944 and distributed by BuShips. This 
handbook covered maintenance and repair of 
all types of sonar equipment in use at the time. 
Some 500 additional pages on new developments 
were issued at a later date. 

In the spring of 1944, NDRC undertook for 
BuShips under its UCDWR contract a project 
to prepare a series of maintenance manuals 
for all types of sonar equipment. A staff of 
some 50 technical writers, editors, artists, and 
clerical assistants was formed in New York 
City. Several Navy officers were also assigned 
to the project by BuShips. Of the thirteen 
manuals planned, the first, a Sonar Equipment 


Log, was issued in May 1944 and was followed 
by others at intervals during 1944 and early 
1945. After February 1945 the work was con¬ 
tinued under a BuShips-UCDWR contract until 
all the projected manuals were published. 

As part of a special training program for 
range recorder operators, members of the Di¬ 
vision 6 training group collaborated with 
AsDevLant, Surface Division, in the prepara¬ 
tion, first, of a preliminary instruction book, 
Interpretation of Sound Range Recorder Traces 
and later of a final book, Operation of the Sound 
Range Recorder (see Figure 5). The latter was 
published and distributed by COMINCH to all 
ASW ships and activities. 

When the Division 6 groups first became ac¬ 
tive in ASW training, a large number of mis¬ 
cellaneous recordings of underwater sounds 
were on hand at the sound schools. Few of 
these were of any value since the material on 
the recordings was not properly identified. In¬ 
complete information was given as to the source 
of sound examples, the kind of equipment used 
in receiving the sound, the range of sound 
source from the receiver, and all the other de¬ 
tails which could make the recordings useful in 
teaching sonar operators. Furthermore, the 
recordings had not been planned with the idea 
of using them for training purposes. 

Since phonograph recordings could be effec¬ 
tive training aids in the field of sonar, the 
recording facilities which had been built up at 
the division laboratories for experimental work 
were used to make training recordings. From 
these a series of five albums of ASW recordings 
was prepared for distribution by BuPers. The 
first three albums, issued in 1943, contained 
(1) examples and explanation of sounds heard 
during echo ranging, (2) exercises to teach 
search and cut-on procedures and echo recogni¬ 
tion, and (3) examples of practice attack runs 
on a submarine. The fourth and fifth albums, 
issued early in 1944, contained a set of drill 
recordings to teach recognition of doppler, and 
examples of sounds produced by torpedoes and 
by the noisemakers used to attract acoustic tor¬ 
pedoes. All recordings were accurately labeled, 
and each album contained an index list as well 
as a pamphlet of directions for the instructor 
(see Figure 6). The ASW training recordings 


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ASSISTANCE TO THE NAVY SOUND SCHOOLS 


25 


(U) TRUNNION PINS (EB ONLY) 


(V) UPPER DRIFT STOP 
SHAFT 

\ 

♦ 

\ 

A 


( $) UPPER CONTACT SWITCH 
ROLLER ARM 

NOTE: THIS EB PNY SIMILAR 



(Q) HAND-TRAINING 
* SHAFT OUTBOARD 

BEARING 


(J) EMERGENCY HAND-TRAINING-STOP 
X HOUSING AND PINION BEARING 
(SEE FIG. 7 FOR DETAILS) 


.... (P) GEAR REDUCER 

-CO) CLUTCH GEAR 

(M) CLUTCH SPIDER 
(E) TRAINING PINION 
(FROM MANIFOLD) 
(SEE FIG. 8 FOR DETAILS) 


(B & D) UPPER THRUST BEARING 

(ANOTHER ON OPPOSITE SIDE 
COMES FROM THE MANIFOLD) 


(A & C) CENTER RADIAL BALL BEARINGS 
(ANOTHER ON OPPOSITE SIDE 
COMES FROM THE MANIFOLD) 


lllllliail WEEKLY 

■■■MB MONTHLY 

■■■■■ BI-MONTHLY OR SEMI-ANNUALLY 


(N) TRAINING MOTOR 
BEARINGS 


( L) TRAINING LIMIT SWITCH 
(POINTS OF LUBRICATION) 


Figure 3. Page from Sonar Maintenance Handbook. 


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26 


TRAINING OF ANTISUBMARINE WARFARE PERSONNEL 



CORRECT m4d . cf go, 



On toe long BDI rang* »#Hing. 
WHoU traca !« compraiiad. 


Fig. 12 Rang* (witch sattings. 



On too ibort BDI rang* teal* 
totting. Echo <• off top of icroon. 


2. Adjust the intensity control so that the 
vertical trace on the BDI screen is barely 
visible. 

3. Set the RANGE switch for the same range as 
that on the Sonar gear. When the Sonar 
gear is being used on some range scale not 
available on the BDI range switch, set the 
BDI RANGE for the next larger value to in¬ 
sure getting a complete trace on the BDI 
screen. (See Fig. 12.) 

4. Set the gain control high enough so that 
you can recognize the echo readily, but not 
so high that the spot will be thrown off the 


BDI screen. In general, there should be an 
echo deflection of about *4 inch, although 
this will decrease as the projector bearing 
approaches that of the target. The exact 
size of the deflection also will vary from ping 
to ping. (See Section D 6.) Note: Varying 
the gain control of the BDI in no way affects 
the gain of the Sonar receiver. 

5. If, at the instant you hear the echo on the 
Sonar loudspeaker, the trace on the BDI 
screen shows a sharp deflection to the right, 
train right. (A right deflection on the BDI 
screen means that the target is to the right 
of the projector bearing.) The distance of 



Fig. 13 Deflections and canter indications of BDI. 


Figure 4. Typical page from the BDI manual. 


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ASSISTANCE TO THE NAVY SOUND SCHOOLS 


27 


Confidential 

The signal sent out by the projector of the echo-ranging gear travels as a disc-shaped disturbance 
in the water. 


The length of this disc remains con¬ 
stant as the disturbance travels out¬ 
ward from the projector. The area of 
the face of the disc, of course, increases. 

When the outgoing signal or ping strikes a target an echo is returned—the disturbance is reflected, 
travels back to the projector which now serves as a receiver, is picked up, heard as an echo on the 
loudspeaker, and appears on the Sonar Range Recorder as a short, dark line. The length of this 
line depends upon the length of the returning disturbance in the water. 

When the target is at right angles to the sonar beam projected against it, all parts of the outgoing 
disc will strike the target at the same time. Consequently, all parts of the disc will be reflected 
and started on their return journey simultaneously. The disc which travels back to the projector 
will be an undistorted image of the outgoing disc. 




The length of the returning disc of disturbance will be equal to that of the outgoing one. More¬ 
over, when it reaches the receiver and is transformed to a short, dark line on the recorder trace, this 
line will be approximately equal in length to the one representing the outgoing signal. 



Figure 5. Page from Operation of the Sonar Range Recorder. 


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28 


TRAINING OF ANTISUBMARINE WARFARE PERSONNEL 


were distributed by BuPers to all ASW ships 
and activities. 

A set of recordings illustrating sounds heard 
over the anchored sono radio buoy was produced 
for BuShips distribution. 


NavPers 11403 RB.—Doppler effect—wake echoes. 

Section 1. Sweeping of submarine target—an example simi¬ 
lar to that on Record. NavPers 11403 RA. 


Section 2. Same as 
section 1 except that 
the echo-ranging ship 
is more nearly dead 
astern of target so that 
sometimes double 
echoes are received, one 
from the wake and one 
from the sub. The true 
echo may be distin¬ 
guished by its low Dop¬ 
pler. (See diagram.) 


Section 3. In this final 
illustration the echo¬ 
ranging ship is "ping¬ 
ing" through the wake 
of another surface craft 
on a moving sub. A 
double echo is heard, 
that from the sub hav¬ 
ing low Doppler. (See 
diagram.) The ptob- 
lem of detecting the 
true echo in this case 
is much the same 
as that when a sub is 
making "knuckles" while employing evasive tactics. 

[7] GonfiJtntisl 


Figure 6. Page from manual for ASW training 
records. 

Recordings were also used with several syn¬ 
thetic trainers. Five albums, 45 recordings, were 
prepared for use with the range recorder 
teacher, and over 100 recordings for the ERGT. 

Assistance was given in preparation of two 
of the early movies for sonar operators. Other 
Navy films were edited and shortened so that 
they were better fitted to the instruction pro¬ 
grams of the schools. Several sets of lantern 
slides were made for classroom use. 

Devices for classroom demonstration were 
designed and constructed in small quantity. The 
“magnetic ocean,” a sheet of metal on which 




several ships attached by magnets could be 
manipulated, was used in demonstrating rela¬ 
tive motion and attack procedures. Other ex¬ 
amples of this type of training aid were the 
animated lantern slides for teaching relative 
bearings and demonstrating search procedures. 


3 ' 2 ' 5 Construction of Synthetic Trainers 

At the beginning of 1942, the only sonar 
equipments available for operator practice were 
those aboard training ships and those which 
were part of the attack teachers. Sometimes as 
many as 50 students had to take turns at a 
single sonar stack. There was a serious need 
for synthetic trainers. 

Bearing Teachers. Work was begun at once 
on a trainer which would resemble the sonar 
stack in appearance and operation, and would 
incorporate an automatic problem generator. 
The first unit of this device, called the advanced 
bearing teacher [QFD], was completed in May 
1942 and four more were ready by the end of 



Figure 7. Advanced bearing teacher. 


June. The advanced bearing teacher (see Fig¬ 
ure 7) had all of the controls of the standard 
sonar stack, so that the student had much of the 
sense of working on real equipment. Range, 
bearing, bearing width, echo intensity, and 
doppler changed during the course of a problem 


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ASSISTANCE TO THE NAVY SOUND SCHOOLS 


29 


much as they would in an actual practice attack. 

To fill the gap until the advanced bearing 
teacher could be produced in quantity, the 
primary bearing teacher [QFE], as shown in 
Figure 8, was hurriedly designed and ten units 
rushed through the UCDWR laboratory shops 


ator and another as problem-setter, while the 
instructor attempted to exercise general super¬ 
vision over a number of such groups. To enable 
a single instructor to handle ten or more stu¬ 
dents effectively, it became evident that a better 
group training method was needed. 



Figure 8. Primary bearing teacher. 


to become available in May and June. Although 
it did not bear too close a resemblance to the 
sonar stack, the primary bearing teacher could 
be used for drill on the more elementary pro¬ 
cedures such as searching, reporting contact, 
crossing the target, and reporting doppler. 

By November 1942, 20 advanced bearing 
teachers and 50 primary bearing teachers had 
been supplied by outside contractors. Still larger 
quantities were later procured by the Navy. 
During early 1943 advanced bearing teachers 
became the backbone of the shore phase of 
operator training. Additional attack teachers 
had been installed, but the time for each stu¬ 
dent at the attack teacher sonar stack was still 
very limited. Primary bearing teachers were 
used only for rudimentary instruction in pro¬ 
cedures. (A miniature version of the primary 
bearing teacher, called the midget bearing dem¬ 
onstrator, was later designed and a few built 
for shipboard use.) 

Group Operator Trainers. The bearing teach¬ 
ers were essentially individual training devices. 
At each instrument one student acted as oper- 


In the summer of 1943 a mass procedure 
teacher was being used by the British in train¬ 
ing sonar operators at Key West. Although 
equipped only with manual controls, this group 
trainer enabled a single instructor to handle 10 
to 20 students quite effectively. Group trainers 
adapted to U. S. Navy sonar equipment were 
devised temporarily at San Diego and Key West 
by enclosing each advanced bearing teacher in 
a sound-deadening booth and monitoring a se¬ 
ries of them from a single central console. The 
success of this group instruction method in the 
winter of 1943-44 led to the development of a 
more refined group trainer for operator prac¬ 
tice. 

Two units of the group operator trainer (see 
Figure 9), one for each sound school, were 
built by UCDWR and installed at the sound 
schools late in 1944. A central master station 
controlled ten standard sonar stacks, each en¬ 
closed in a sound-deadening booth. An auto¬ 
matic problem generator provided a selection 
of six different attacks. Each student operated 
his stack independently. Repeaters on the cen- 


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30 


TRAINING OF ANTISUBMARINE WARFARE PERSONNEL 


tral console indicated the movements of each 
projector, while a monitoring system enabled 
the instructor to listen in on any selected booth 
and give special instruction as needed. An im¬ 
portant improvement over the advanced bear¬ 
ing teacher was the provision of a wake echo 
in addition to the submarine echo. 


livered to ASW training centers. Two models 
of improved design served as production proto¬ 
types for the construction of 53 units which 
were built at the U. S. Navy Underwater Sound 
laboratory and distributed to the sound schools 
and other training activities. 

This was a group trainer (see Figure 10) 



INTERCOM 

MICROPHONE- SPEAKER 
BEARING 

DIALS. CONTROL 


BEARING- 


— GRADING 
RECORDER 



Figure 9. Group operator trainer. 


Sound Range Recorder Trainers. By 1943 the 
sound range recorder had become an important 
part of ASW sonar equipment. Although range 
recorders had been installed on attack teachers, 
neither the traces nor the accompanying sounds 
were realistic. All practical drill in trace recog¬ 
nition had to be given during the sea phase of 
training. 

In the spring of 1943 work was started at the 
CUDWR laboratory on the sound range recorder 
teacher [QFL]. Six laboratory-built units were 
completed by late summer and five of them de- 


which used phonograph recordings of practice 
attacks to actuate a bank of five or more record¬ 
ers and simultaneously produce authentic ac¬ 
companying sounds. A 75-c tone, filtered out of 
the audio circuit, initiated stylus movement at 
the instant of each outgoing ping. Reverbera¬ 
tions and echoes printed traces on the recorder 
paper exactly as on a shipboard installation. 
Each student was free to operate all the controls 
on his recorder independently, as he would in an 
attack. Five albums of recordings provided 
elementary instruction in operation of controls, 


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31 


demonstrations of various target aspects and 
changes of aspects, and a series of firing drills 
of graded difficulty. Each drill required the stu¬ 
dent to determine target aspect, set up the fir¬ 
ing analyzer, judge the range rate, and fire at 
the proper time. An analysis of errors in report¬ 
ing target aspect, setting range rate, and firing 


opaque projector. Several units were built but 
saw little actual service, because it was difficult 
to obtain clean-cut projected traces except 
under ideal conditions in a dark room. 

A cardboard model chemical recorder, in 
which printed traces could be inserted, as de¬ 
signed by the training group at Key West and 



Figure 10. QFL range recorder teacher in operation. 


gave evidence of the student’s progress. With 
the recordings which had been selected, the 
trainer provided practice on a wider range of 
attack situations than could be obtained during 
the sea phase of training. 

A device called the recorder trace projector 
was designed as a classroom aid for teaching 
recorder operations to large groups. It consisted 
of a large-scale model of the sound range re¬ 
corder face and firing time analyzer, with the 
window in the face replaced by a projection 
screen. Traces from an operating range re¬ 
corder teacher or attack teacher recorder could 
be projected on the screen by means of an 


distributed by BuPers to training activities. A 
plastic elementary range recorder teacher, also 
using printed recorder traces, was designed by 
UCDWR and 25 units furnished to the sound 
school at San Diego. Both devices were largely 
replaced, even for elementary training, by the 
more effective range recorder teacher. 

Echo Recognition Group Trainer. Through¬ 
out 1942 and 1943, a gradual evolution was tak¬ 
ing place in the use of phonograph recordings 
for training sonar operators and sonar officers. 
Demonstration records, which had been pro¬ 
duced for wide distribution to ships and train¬ 
ing centers, were being replaced at the schools 


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TRAINING OF ANTISUBMARINE WARFARE PERSONNEL 


by drill recordings which required more active 
participation of the students, and by test re¬ 
cordings which gave measures of progress. 
ERGT was the culmination of this development. 



Figure 11. Echo recognition group trainer in 
use. 


The first model was completed early in 1944 and 
improved designs were later installed at both 
sound schools (see Figure 11). 

The echo recognition group trainer provided 
a central console from which an instructor could 
monitor drills and tests for a group of 10 to 20 
students. Each student station was equipped 
with a silent switch for signaling answers. The 
signals were recorded graphically on a moving 
web of paper, giving an individual record for 
each student. Thus errors could be corrected 
and tardy responses noted immediately. 

Each drill exercise was planned to give 
specific training in one or more types of sound 
discrimination, such as detecting faint contacts, 
distinguishing echoes through heavy reverbera¬ 
tions, and distinguishing submarine echoes 
from wake echoes. Standardized tests meas¬ 
ured student progress. Both drill and test mate¬ 
rials were continually refined throughout 1944 
and early 1945. 

Attack Teacher Improvements. Minor im¬ 
provements were made on the Sangamo attack 
teacher. A simple but useful change was the 
addition of a projected azimuth grid which 
permitted the instructor to maintain a constant 
check on the accuracy of reported target bear¬ 


ings. An experimental model of a depth charge 
pattern recorder was built as an adjunct to the 
depth charge driller on one of the attack teacher 
installations at Key West. Developed in a more 
refined form, this device was furnished to vari¬ 
ous training activities during 1944. 

Practice Targets. In the spring of 1942, the 
sea phase of operator and officer training was 
seriously handicapped by a lack of sufficient 
target submarines for practice attacks. There 
was an immediate need for some sort of syn¬ 
thetic target to replace the missing submarines. 
The first repeater targets were laboratory-built 
and put into service that fall. Later on, many 
units of improved models were procured by the 
Navy and furnished to training activities. 

The earliest models of practice targets were 
attached to a towed raft or to the keel of a 
small target vessel. Barrel-type stationary re¬ 
peaters were also used for the most elementary 
instruction. To permit the attacking ship to 
maneuver freely, however, it was necessary to 
have a submersible repeater target which could 
be towed by a long line. Model SR-2, which 
operated at a depth of 60 to 90 ft at the end 
of a 1,200-ft towline, was produced in quantity 
during 1943 (see Figure 12). A few units of 



Figure 12. Echo repeater practice target, model 
SR-2, Navy designation OAS. 

an improved model (SR-5) were used in 1944. 

Essentially the same repeater mechanism, 
roughly simulating the return of echoes from 
a submarine, was used in all these practice 
targets. Doppler effect was produced if the re¬ 
peater was moving. The best repeaters were 
not a perfect substitute for actual submarine 
targets since the traces received on the sound 
range recorder were oversimplified, principally 


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ASSISTANCE TO THE NAVY SOUND SCHOOLS 


33 


because of the absence of wake effects. They 
proved extremely useful, however, in providing 
sea training for operators and officers during a 
period when sufficient submarines were not 
available. 

Shipboard Attack Teachers. Another problem 
of growing importance was the need for some 
sort of shipboard training for the members of 
the sonar team after they left sound school. Op¬ 
portunities for ASW vessels to make runs on our 
own submarines were rare, and there was no 
synthetic method of simulating an attack. Skills 
which had been well developed in sound school 
became inadequate from disuse. 

Early in 1943, the UCDWR laboratory de¬ 
signed a simple electronic device which, when 
attached to the sonar stack aboard ship, could 
provide artificial echoes. Only a few of these 
echo injectors were built, since their usefulness 
was limited mainly to checking the alertness of 
the sonar operator on watch. 

During 1943, development proceeded on the 
more complicated shipboard antisubmarine at¬ 
tack teacher [SASAT-A]. SASAT-A could be 





Figure 13. SASAT installed at a shipboard 
sonar stack. 

taken aboard a vessel and hooked directly into 
the sonar stack without interfering with nor¬ 
mal operation (see Figure 13). The injected 
echo could be altered as to bearing, intensity, 
and doppler by manual control. The range of 


echo decreased automatically in accordance 
with the setting of a range-rate dial. Thirty 
units of SASAT-A, Model IV, were laboratory- 
built during the winter of 1943-44 and 100 
units were later procured by the Navy. An ex¬ 
perimental unit of Model V, incorporating BDI 
effects and equipped with true bearing dial 
coupled to the ship’s gyro, was completed but 
never produced in quantity. 

SASAT-A proved most valuable for drilling 
the members of the sonar team in passing in¬ 
formation and working smoothly together. It 
was also useful in providing refresher practice 
for sonar operators, although the echoes and 
recorder traces were oversimplified like those 
from a repeater target. A manual, giving the 
proper sequence of SASAT settings for simulat¬ 
ing standardized attacks, was supplied as a 
guide in sonar team and operator training. 

In some few instances, it was found pos¬ 
sible to use SASAT-A for conning officer prac¬ 
tice. For this purpose, however, no prepared 
sequence of settings could be employed. The 
SASAT controls had to be adjusted on the spot 
according to the maneuvers ordered by the con¬ 
ning officer. Few SASAT operators possessed 
the necessary skill in visualizing relative move¬ 
ment and simultaneously manipulating the dials 
to produce realistic effects. A SASAT slide rule 
for solving the relative movement problems was 
only a partial remedy. The obvious solution 
was a shipboard attack teacher employing an 
automatic problem generator. Such a device 
(SASAT-B) underwent experimental develop¬ 
ment, but never saw actual service. 

Primary Conning Teacher. The primary con¬ 
ning teacher , as shown in Figure 14, was orig¬ 
inally conceived as a device for the elementary 
training of ASW conning officers. Five experi¬ 
mental models were completed by the CUDWR 
laboratory in 1943 and 100 additional produc¬ 
tion models were procured by the Navy early in 
1944. 

In essence, the primary conning teacher was 
a miniature attack teacher without sound. The 
target was represented by a spot of light ap¬ 
pearing on a maneuvering board screen. Target 
range and bearing were altered automatically 
to simulate the relative movement of ship and 
submarine. The problem-setter adjusted the 


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34 


TRAINING OF ANTISUBMARINE WARFARE PERSONNEL 


speed and course of the submarine. The student 
conning officer directed the attacking ship by 
means of speed and rudder controls and pushed 
a button to indicate the dropping of depth 
charges or the firing of forward throwers. The 
accuracy of the attack could then be scored. 

By the time production units were delivered, 
sufficient attack teachers had been installed at 


33 LIAISON 

Liaison with ASW activities other than the 
sound schools was maintained through the Com¬ 
mittee on Selection and Training, through 
special training representatives assigned to 
various training commands, and through con¬ 
tact with organizations such as the BuShips 



Figure 14. Primary bearing teacher. 


the sound schools and other ASW training cen¬ 
ters to provide adequate training facilities for 
conning officers. A few units were used for 
shipboard conning instruction but the majority 
were employed as problem generators for exer¬ 
cises in plotting, for simulating two-ship at¬ 
tacks on the attack teacher, and for CIC train¬ 
ing. 

326 Instructors 

In the summer of 1942 men with electronic 
training and teaching experience were recruited 
to serve as instructors in the sonar materiel 
schools at San Diego and Key West. They were 
employed by Division 6 until early in 1944, at 
which time they were replaced by Navy instruc¬ 
tors or were given Navy commissions and re¬ 
tained. 

In order to introduce new trainers or to initi¬ 
ate instruction on new equipment, members of 
the training group served as instructors for 
limited periods. Experimental instruction pro¬ 
grams for the QFL and ERGT trainers were 
carried on for several months. 


field engineers and the Antisubmarine Warfare 
Operational Research Group. 

The Committee on Selection and Training 
met at frequent intervals with representatives 
of various branches of the Navy—COMINCH, 
BuPers, BuShips, Coordinator Research and 
Development, BuMed, and others—to report on 
progress of work undertaken and to lay plans 
for new work. Individual members of the Com¬ 
mittee also paid frequent visits to ASW train¬ 
ing centers. 

From June 1943 until March 1944, a training 
representative worked closely with COMINCH 
on several special training projects, most im¬ 
portant of which were the training program 
for operators of the sound range recorder and 
the production of ASW training recordings. 

A training representative assigned to 
COTCLant late in 1943 assisted the Antisub¬ 
marine Warfare Unit in a variety of ways. He 
compiled priority lists for the distribution of 
training equipment, organized an index of in¬ 
structors, and acted as an advisor to the subor¬ 
dinate training activities. A representative as¬ 
signed to ComDesPac served as both a training 


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TRAINING PROGRAMS FOR LABORATORY DEVELOPMENTS 


35 


assistant and a field engineer. He helped not 
only in installing training equipment and start¬ 
ing training courses but also in the develop¬ 
ment, during training exercises, of new methods 
of attack. 

Representatives of Division 3 and Division 6 
were primarily responsible for instruction, 
given at San Diego, Key West, and Bermuda 
during 1943 and 1944, on the use of the “mouse¬ 
trap.” They directed loading and firing drills 
and analyzed and tabulated results of practice 
attacks. 

Members of the training groups stationed at 
the sound schools and laboratories made in¬ 
creasingly frequent visits to ASW training cen¬ 
ters during 1943 and 1944 in order to intro¬ 
duce new trainers or to assist in starting new 
courses. 

The BuShips Field Engineers, although 
mainly concerned with engineering problems, 
took an active part in maintenance and operator 
instruction. They maintained close contact with 
the division laboratories and training groups. 
The Antisubmarine Warfare Operational Re¬ 
search Group [ASWORG] was an important 
source of information since it was often able 
to point to defects in training which showed up 
in operational results. 


34 TRAINING PROGRAMS FOR 
LABORATORY DEVELOPMENTS 

To get their products into use as quickly as 
possible, it was necessary for the research and 
development laboratories to assume certain re¬ 
sponsibility for the organization of suitable 
training programs. 

In retrospect, it is easy to see that a complete 
training program for a new piece of equipment 
should include the following: (1) operational 
research to discover the best procedures for its 
use, (2) development of training courses for 
operators and maintenance men, (3) prepara¬ 
tion of operator and maintenance manuals, 
(4) design and construction of synthetic train¬ 
ers, and (5) field service to initiate the train¬ 
ing program. Under the stress of wartime con¬ 
ditions, such a systematic plan was not always 
followed. 


Operational research was usually inadequate. 
During the period of experimental development, 
main attention was focused on getting the bugs 
out of the equipment, and any operational re¬ 
search was incidental. When the first produc¬ 
tion models appeared, they were sent directly 
to ships for installation. This policy was later 
changed so that early production models were 
earmarked for training schools, thus permitting 
some study of their proper utilization before 
many service installations had been made. 

Plans for training courses had to be based on 
whatever experience the laboratory had been 
able to accumulate during field tests. Typically, 
the training course for operators as first 
planned was found to need considerable revi¬ 
sion as Service experience with the equipment 
accrued. Maintenance instruction was usually 
satisfactory for the problems encountered dur¬ 
ing engineering development but had to be 
modified and expanded as information on field 
casualties became available. 

Manuals were prepared in provisional form, 
because it was necessary to have instruction 
books to accompany the first equipments going 
into the field. These instructions were adequate 
for installation, routine operation, and normal 
maintenance but reflected the limitations of 
laboratory experience with service conditions. 
Whenever possible, the provisional manuals 
were later replaced by more complete instruc¬ 
tion books. 

Construction of synthetic trainers, if any 
were required, was usually under way before 
the final engineering development of the new 
equipment had been completed. However, a syn¬ 
thetic trainer often involved as difficult a set of 
design and construction problems as the origi¬ 
nal equipment. Consequently, only experimental 
models of trainers were ready by the time the 
first production units of new equipment went 
into service. 

Field representatives did a great deal to 
make the training programs work under diffi¬ 
cult conditions. Using whatever materials were 
available, they got courses started and trained 
Navy instructors to take over. They supervised 
the installation and demonstrated the use of 
synthetic trainers. When standard equipment 
was available, they assisted in making suitable 


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36 


TRAINING OF ANTISUBMARINE WARFARE PERSONNEL 


training installations. Through their intimate 
contact with many different groups, they gath¬ 
ered a wealth of suggestions for improving 
training methods. 


3 41 BDI Program 

The bearing deviation indicator [BDI], de¬ 
veloped by the Harvard Underwater Sound 
Laboratory [HUSL], was one of the few radi¬ 
cal changes in U. S. sonar gear introduced dur¬ 
ing World War II. Instead of intermittent 
reports of cut-ons, BDI made possible continual 
and accurate center bearings of the target. 

Since the maintenance problem was crucial, 
first attention was given to training the field 
engineers who were to supervise the installation 
of BDI equipment on ships. Beginning in 1943 
as a series of informal lectures and demonstra¬ 
tions, the program was crystallized in Febru¬ 
ary 1944 into a one-week course which was 
given at HUSL. The course covered the details 
of installation, adjustment, routine mainte¬ 
nance, trouble-shooting, operation, and the fun¬ 
damentals of BDI trace interpretation. The 
BDI dynamic demonstrator, together with a 
signal injector (OTE-9), was designed and 
seven units were built for use in maintenance 
instruction. In collaboration with the instruc¬ 
tional staff of ASWIS, BDI maintenance and 
operation instruction was introduced as part 
of the course for ASW specialists. 

For operator instruction, HUSL designed and 
constructed four different types of synthetic 
trainers, OTE-2, OTE-4, OTE-5, and OTE-8. 
OTE-2, when connected to a standard shipboard 
sound stack, supplied artificial reverberations 
and echoes. Program cams were used to change 
range, bearing, and doppler in simulation of 
an attack. A graphic record was made of the 
correct bearings and the bearings obtained by 
the student. Only one unit was constructed; 
this was used for experimental work on the 
USS Sylph, one of the ships attached to 
AsDevLant. OTE-4 was an interim modification 
designed to furnish input signals to BDI equip¬ 
ment used with the Sangamo attack teacher. 
Only three units were constructed, because later 
modification of the attack teacher by the San¬ 


gamo Electric Company made the device un¬ 
necessary. OTE-5 modified the QFA-5 attack 
teacher to operate with QH-type sonar or to 
provide typical QH displays on the General 
Electric Company attack plotter. OTE-8 was an 
attachment for the QFD advanced bearing 
teacher (see Figure 15). It provided a BDI 



Figure 15. OTE-8, BDI attachment for the ad¬ 
vanced bearing teacher. 


scope and the necessary equipment to produce 
BDI traces from the bearing teacher signals. 
Twenty-five units were procured by the Navy. 

During 1944 one model of a BDI adjunct for 
the advanced bearing teacher was constructed 
by the UCDWR laboratory. BDI simulation was 
also included in the group operator trainer. 
Since the group operator trainer was provided 
with a wake echo as well as a submarine echo, 
the BDI traces produced were more realistic 
than on any of the other training devices. 

Instruction of officers in the use of BDI suf¬ 
fered from the delay in developing conning pro¬ 
cedures based on the use of center bearings. At 
the time BDI became available, the official con- 


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TRAINING PROGRAMS FOR LABORATORY DEVELOPMENTS 


37 


ning doctrine was based on the use of leading 
cut-ons and was totally unsuitable when BDI 
was used. Considerable confusion existed until 
an official method of BDI conning was finally 
adopted. 


Bathythermograph Program 

The first bathythermographs [BT] were sup¬ 
plied to ASW vessels early in 1942. At the re¬ 
quest of BuShips, the Woods Hole Oceano¬ 
graphic Institution [WHOI] gave a month’s 
course on the bathythermograph to three sepa¬ 
rate groups of BT officers. These officers were 
sent out to various commands, but many of 
them were assigned to other activities, only a 
few continuing in BT work. 

Meanwhile informal instruction, first given 
occasionally to a few officers at WHOI, had been 
expanded by late 1943 into an intensive five-day 
course for ASW instructors and specialist stu¬ 
dents from ASWIS. During the following year 
some 600 officers attended this course. Field 
men from WHOI, although primarily engaged 
in gathering BT data for analysis, found many 
opportunities to give on-the-spot instruction at 
various ASW training activities. During 1942 
and 1943, aid was given by WHOI in the prep¬ 
aration of BT manuals published by BuShips. 

By 1944 research on the prediction of sound 
ranges from BT observations had produced 
much new information. In June 1944 UCDWR, 
in collaboration with BuShips, undertook a pro¬ 
gram of manual revision and of refresher in¬ 
struction. Between June and October 1944 rep¬ 
resentatives visited training activities on the 
Atlantic and Pacific coasts, in the Mediterranean 
area, and in Africa and Brazil, giving instruc¬ 
tion on the latest range-prediction methods. 
They worked closely with ASW instructors who 
were directing refresher training. Preparation 
of BT manuals continued through 1944 and 
1945. 


3.4* 3 ERSB and DRSB Program 

The previous sections of this chapter have 
dealt with the training of officers and men of 


surface craft. The expendable radio sono buoy 
[ERSB] and the directional radio sono buoy 
[DRSB] were sonar detecting devices dropped 
from aircraft. The officers and men trained to 
use and maintain these devices were, for the 
most part, from the air forces. 

In the late summer of 1942, instruction books 
and training recordings for the ERSB were 
prepared by the CUDWR laboratory and dis¬ 
tributed to Army and Navy groups which were 
testing the first experimental models of the 
buoy. During February and March 1943, sev¬ 
eral groups of Army Air Force and Navy offi¬ 
cers and men were sent to the Naval Training 
School, Fisher’s Island, and given a special 
course on the use and maintenance of buoy 
equipment. The program was planned and to 
a large extent conducted by members of the 
CUDWR staff. The officers and men trained at 
Fisher’s Island returned to their stations to in¬ 
struct the crews of planes receiving the first 
production units. 

Engineers who had worked with the ERSB 
development group in the CUDWR laboratory 
visited the Army and Navy bases where ERSB 
equipment was being used, supervised the in¬ 
stallation of receivers in planes, directed the 
testing and readying of buoys, and assisted in 
the training of operators, maintenance men, 
and flight crews. This field service was a major 
factor in the effective use of the ERSB. During 
1943, 1944, and early 1945, three to eight lab¬ 
oratory representatives were engaged in field 
work throughout all areas in which extensive 
training was being carried on: the Caribbean, 
North Atlantic islands, England, the Mediter¬ 
ranean, and the Pacific. Their work was sup¬ 
plemented in 1944 by the Aircraft Coordinating 
Group organized under the Naval Research 
Laboratory. Members of the Aircraft Coordi¬ 
nating Group were given special instruction in 
the use and maintenance of buoy equipment at 
New London and at the ComAirLant Sono Buoy 
School in Norfolk. 

In the spring of 1943, as the production of 
ERSB equipment increased, additional training 
materials were required. Three 15-minute slide 
films with sound, describing the ERSB and how 
to use it, were produced by CUDWR and dis¬ 
tributed by BuAer. The ERSB trainer, which 


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38 


TRAINING OF ANTISUBMARINE WARFARE PERSONNEL 



operated from phonograph recordings, was de¬ 
signed and two units built, one for AsDevLant 
at Quonset and the other for ComAirLant at 
Norfolk. Instruction books were revised to cover 
modifications in the equipment and new features 
of its use. 

A sono buoy school was established by Com¬ 
AirLant at Norfolk in May 1944. The CUDWR 
staff trained instructors for this school, helped 
them in planning lectures and laboratory ses¬ 
sions, and conducted part of the courses during 
the early days of the school. On several later 
occasions, instructors from the school were 
given special courses at the laboratory. 

During the summer of 1944, a new set of 
ERSB phonograph recordings, giving more ex¬ 
tensive examples of ship sounds, was completed 
and turned over to BuAer for distribution. A 
training program for DRSB, which was then 
getting into production, was also initiated. Op¬ 
eration and maintenance instruction books were 
written, a set of phonograph recordings pre¬ 
pared, a descriptive movie produced, and a syn¬ 
thetic trainer constructed (see Figure 16). All 
of these were completed and ready for use by 
the time the first production units of DRSB 
were delivered. Instructors from the ComAir¬ 
Lant Sono Buoy School were given special 
training on DRSB. Courses in operation and 
maintenance were outlined and introduced at 
the ComAirLant school. 

During the spring of 1945, the activities of 
CUDWR in connection with ERSB and DRSB 
training gradually decreased as the programs 
of the ComAirLant school and the Aircraft Co¬ 
ordinating Group became fully effective. 


344 MAD Program 

The magnetic airborne detector [MAD] was 
developed by the Airborne Instruments Labora¬ 
tory [AIL], Mineola, L. I. All assistance to the 
Navy in training men to use and maintain MAD 
was handled by the laboratory personnel. 

Between September 1943 and June 1944, 346 
officers and men attended courses at Mineola 
for pilots, operators, and technicians. The pilot 
and operator courses were each two weeks in 
length, with pilots and operators paired in 


Figure 16. DRSB trainer in operation. 


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ASW TRAINING AIDS 


39 


teams during the last two days. The techni¬ 
cian’s course lasted four or five weeks and con¬ 
centrated primarily on practical maintenance 
and trouble shooting. For the elementary train¬ 
ing of operators, a setup of eight standard MAD 
equipments was used, with a signal generator 
to furnish magnetic indications simultaneously 
to all stations. 

Two synthetic trainers were developed by 
AIL. a The pantograph tactics trainer was de¬ 
signed to teach the elements of MAD tactics to 
pilots. The student pilot on one side of a screen 
traced a search pattern, while an instructor on 
the other side reported each time the pilot 
made contact with a simulated submarine track. 

The magnetic attack trainer was an elaborate 
device in which a model submarine and a model 
airplane were maneuvered by remote controls. 


a See STR Division 6, Volume 5, Chapter 7. 


The model submarine generated a magnetic field 
scaled to that of an actual submarine. The 
model plane was equipped with a detector which 
produced MAD indications at the pilot’s station 
whenever the plane came within proper range 
of the submarine. Duplicate MAD indications 
were produced at the operator’s station, so that 
the pilot and operator could be trained as a 
team. A later model of the device, including 
both MAD and ERSB signals, was constructed 
to simulate blimp operation. Pilots and operators 
were given some training in the use of the 
ERSB as well as MAD. 

»■» ASW TRAINING AIDS 

Phonograph recordings, slides and films, and 
classroom teaching devices prepared by Divi¬ 
sion 6 are listed in Appendix III. Instruction 
books are listed in the bibliography. 


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Chapter 4 

SELECTION OF SUBMARINE PERSONNEL 


IVISION 6 did NOT participate extensively in 
research on the selection of submarine per¬ 
sonnel, but it did on several occasions supply 
technical assistance for limited periods. For six 
months during 1942, a psychologist and a cleri¬ 
cal assistant worked with the Medical Research 
Department, Submarine Base, New London, on 
a research program for sonar operator selec¬ 
tion. Further incidental assistance was given 
to the same department at a later date. From 
June through December 1944, three members 
of the training group worked with ComSub- 
TrainPac in developing a system of personnel 
classification and establishing entrance require¬ 
ments for submarine training courses at Pearl 
Harbor. 


41 SELECTION FOR SONAR OPERATOR 
COURSES 

The problem of selecting men to be given 
submarine sonar operator training was quite 


Table 1. Complement for submarines of the 
Salmon (SS182) class. 


Rate 

Standard 

complement 

Eligible to 
stand 
sonar 

watch 

Eligible 

but 

seldom 

assigned 

Not 

eligible 

GM 

1 

1 



TM 

7 


7 


TME 

2 


2 


QM 

3 


3 


SM 

1 


1 


FCS 

1 

1 



S 

11 

11 



RM 

4 

4 



RT 

2 

2 



MoMM 

16 



16 

EM 

10 



10 

F 

4 



4 

Y 

1 

1 



PRM 

1 

1 



SC 

2 


2 


Bkr 

1 


1 


StM 

2 


2 


Total 

69 

21 

18 

30 


different from the parallel problem which had 
been encountered in the Antisubmarine War¬ 


fare [ASW] work. There was no rating of 
submarine sonarman prior to February 1945. 
Seamen and men rated in certain other special¬ 
ties were assigned to stand sonar watches. 

It was considered desirable to have approxi¬ 
mately 14 men per boat trained in sonar opera¬ 
tion. Table 1 shows that the ship’s complement 
included only 21 men in the rates usually as¬ 
signed to sonar duty. This meant that at least 
two-thirds of the men in these ratings had to be 
given sonar operator training. Contrast this 
situation with that for surface craft where the 
best operator material could be chosen from 
large training camp populations. For subma¬ 
rines, the primary problem was to eliminate 
men who were dangerously deficient or inept, 
rather than to select the best qualified. The ad¬ 
dition in February 1945 of one rated sonarman 
to each boat’s complement made little differ¬ 
ence, since the majority of sonar watch-standers 
still had to come from other rates. 

The Medical Research Department, Sub¬ 
marine Base, New London, had begun the study 
of sonar operator selection methods in 1941. 
Early in 1942 a psychologist was assigned by 
Division 6 to work with the Medical Research 
Department in planning a testing program and 
analyzing the results, coordinating this investi¬ 
gation with the research at Key West and San 
Diego on selection of surface craft sonar opera¬ 
tors. 

During the spring of 1942, selection tests 
were administered experimentally to students 
entering the sonar operator course at the 
Submarine School. The battery included the 
Otis Test of Mental Ability, all the tests of the 
new edition of Seashore Measures of Musical 
Talent, and an Individual Pitch Discrimination 
Test which had been developed locally. Final 
grades in the operator course were used as 
criteria in validating combinations of the test 
results. For eliminating the men most likely 
to fail, a scheme using the Otis, Seashore Pitch 
and Rhythm, and the Individual Pitch Discrimi¬ 
nation tests as three successive hurdles was 
found to be effective. 



40 


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SELECTION FOR SONAR OPERATOR COURSES 


41 


Results 11 with an experimental group of 121 
students in the submarine sonar operator 
course are shown in Table 2. This battery 
of tests and standard audiometer measure- 

Table 2. Validation of the submarine sonar 
operator selection plan.* 

Submarine School , New London (Criterion, 
final grades) 

Unsatis- Satis¬ 
factory factory Number 

Passed all 3 hurdles 20% 80% 70 

Failed one or more 53% 47% 51 

* Passing scores •on tests were Otis, 36; average of Seashore Pitch 
and Rhythm, 45; and Individual Pitch Discrimination, 35. All scores 
are standard scores based on a mean of 50 and standard deviation 
of 10. The table may be read as follows: Of the 70 men who suc¬ 
cessfully passed all three hurdles, 80% made satisfactory grades in 
the sonar operator course; 20% unsatisfactory, and so on. 

ments were used thereafter as a basis for 
telling the Submarine School which men were 
least qualified and which were best qualified 
for sonar operator training. 


411 Audiometer Studies 

Several investigations were conducted in con¬ 
nection with the use of audiograms in sonar 
operator selection. The classification scheme 
shown in Table 3 was adopted in order that 
audiograms might be grouped for statistical 
study/ 

Based on the classification of Table 3, an 
abbreviated procedure for determining audio- 
grams was developed. 12 Each of 1,050 audio- 
grams was classified twice, first using the 
threshold measurements made at seven fre¬ 
quencies (128, 256, 1,024, 2,048, 4,096, 8,192) 
and then using the measurements for only four 
frequencies (256, 1,024, 4,096, 8,192). It was 
found that every ear classified as deficient by 
the seven-frequency audiogram was also classi¬ 
fied as deficient by the four-frequency audio- 
gram. In only 7 of the 149 deficient cases was 
there a change in the nature of the deficiency 
classification. On the basis of this evidence, the 


a This method of classifying audiograms was devised 
by E. G. Wever, Princeton University. It is a modifica¬ 
tion of a scheme originated by S. R. Guild, Johns 
Hopkins University. 


four-frequency audiogram was used for the 
routine testing of sonar operator candidates. 

A study was made of the value of audiograms 
in predicting listening ability. 13 Student opera¬ 
tors were classified as having “normal” or “de¬ 
ficient” hearing. The normal group included the 


Table 3. Classification of audiograms. 


Classification 

Definition 

N 

Includes all audiograms whose general 
course is not lower than 15 db below 
normal. For one or two tones a loss of 
25 db is allowed if all others are 15 db 
or less. 

D1 

General hearing loss from 20 to 35 db at 
all frequencies. Curve of audiogram 
straight with no marked dips or slope. 

D2 

General hearing loss from 40 to 55 db at 
all frequencies. Curve of audiogram ap¬ 
proximately straight. 

D3 

General hearing loss 60 db or more at all 
frequencies. Curve of audiogram ap¬ 
proximately straight. 

NDl 

Local hearing loss of 30 to 35 db in a 
range of one octave or less. 

ND2 

Local hearing loss of 40 db or more in a 
range or one octave or less. 

HI 

High-frequency hearing loss 40 db or 
more at 16,384 c. Other frequencies 
normal. Since audiograms are commonly 
run only for frequencies through 8,192, 
the HI class is usually considered normal 
(N). 

H2 

High-frequency hearing loss, 40 db or 
more at 8,192 and above. Hearing for 
lower frequencies normal. 

H3 

High-frequency hearing loss, 40 db or 
more at 4,096 and above. Hearing for 
lower frequencies normal. 

H4 

High-frequency hearing loss, 40 db or 
more at 2,048 and above. Hearing for 
lower frequencies normal. 

D1-H2, etc. 

Combinations of above for audiograms 
which cut across classes. 


following audiogram classifications for the two 
ears: both N, N and ND1, ND1 and ND2, N 
and H2, ND1 and H2, HI and H2. All others 
were classed as deficient. Out of a total of 1,700 
subjects, 1,344 (79.1 per cent) were classified 
as normal and 356 (20.9 per cent) as deficient. 
The two groups were compared on the basis of 
various criteria, such as final grade in the oper¬ 
ator course and scores on test target contacts 
during operation of listening equipment. For 
all criteria, the group classified as normal was 
slightly superior. The most significant results 


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42 


SELECTION OF SUBMARINE PERSONNEL 


were obtained with the criterion of contact de¬ 
tection scores made on sonic listening equip¬ 
ment. These results are shown in Table 4. 

Table 4. Influence of hearing loss on listening 
performance. 

New London (Criterion, scores on contact detection 
tests using sonic listening equipment) 

Unsatis- Satis¬ 
factory* factory Number 
Men with “normal” hearing 18% 82% 107 

Men with “deficient” hearing 35% 65% 23 

* Lowest 20 per cent of the group in contact detection scores. 


41-2 Later Assistance 

Active aid to the Medical Research Depart¬ 
ment was discontinued in October 1942 because 
of the greater urgency of other aspects of the 
selection and training programs. In 1944 and 
1945, when the division had become involved in 
the training of submarine sonar operators, in¬ 
terest in the problem of selection was renewed; 
it was considered secondary, however, to that 
of training. 

Preliminary experiments by the training 
group indicated that a testing procedure using 



Figure 1. Propeller noise discrimination meter. 

the propeller noise discrimination meter 14 (see 
Figure 1) could be made sufficiently reliable for 
group testing purposes. 15 Target Discrimination 
Test recordings were also prepared in order to 


measure the student’s ability to pick out a par¬ 
ticular ship’s propeller sounds from several simi¬ 
lar propeller sounds, all recorded over standard 
submarine sonar listening equipment. The test 
had good face-validity, since it was essentially 
a job sample; satisfactory reliability was in¬ 
dicated in preliminary experiments. 10 Both the 
propeller noise discrimination meter and the 
target discrimination test recordings were 
turned over to the Medical Research Depart¬ 
ment for further experimentation. 


413 Discussion 

It has already been pointed out that no sys¬ 
tematic program of submarine sonar operator 
selection research was attempted by Division 6. 
If all men who stand sonar watches were rated 
as sonarmen or if some joint rating such as 
Communications Mate were established to cover 
operators of sonar, radar, and radio equipment, 
such a program might be worth while. It might 
then be possible to select the best-qualified men 
from a relatively large group, preferably before 
their assignment to submarine service. 

A number of suggestions can be made about 
any further research on the selection of sub¬ 
marine sonar operators. 

1. Before any marked advance can be made 
in selection methods, better criteria, i.e., better 
measures of operating skill under realistic con¬ 
ditions, must be obtained. Grades on written 
examinations are of little value. Measures of 
performance on well-designed synthetic trainers 
or on standard equipment during underway 
training may be used if reliable scoring meth¬ 
ods can be developed. Measures of performance 
under conditions of excitement and stress are 
also necessary although difficult to obtain. 

2. Tests which predict ability to perform 
under stress should be developed. Such tests 
cannot, however, be validated until the criteria 
mentioned above are available. 

3. Comparisons should be made of the merits 
of tests which measure relatively discrete apti¬ 
tudes (e.g., pitch discrimination) and tests of 
the job-sample type (e.g., the target discrimi¬ 
nation test previously described). 

4. New tests to measure the total pattern of 


RESTRICTED 










CLASSIFICATION PROGRAM FOR COMSUBPAC 


43 


sensory-motor skills required in operating sonar 
equipment should be devised and tried. 

5. The selection program should be re-ex¬ 
amined at frequent intervals. Each change in 
design of sonar equipment means a change in 
the operator requirements, and the battery of 
selection tests must be revised to keep pace. 

42 CLASSIFICATION PROGRAM FOR 
COMSUBPAC 

In July 1944, a Division 6 group working with 
ComSubPac was asked to assist in establishing 
systematic methods for selecting men to attend 
the various training courses conducted by Com- 
SubTrainPac at Pearl Harbor. In response to 
this request, the following program was pro¬ 
posed 17 : 

1. That a classification system be established 
to determine the capabilities of every enlisted 
man assigned to ComSubPac at Pearl Harbor. 

2. That the classification be based upon the 
tests in the Navy basic battery plus additional 
information as to education, experience, and 
interests obtained by means of a written ques¬ 
tionnaire. 

3. That the test scores and other pertinent 
information for each man be recorded on a 
qualification card, one copy of which would be 
placed in the man’s service record folder and 
the second filed by ComSubTrainPac. 

4. That entrance standards be established 
for every course on the basis of preliminary 
research studies and that all men assigned to 
any course be required to meet its standards. 

5. That a program of research be continued 
in order to improve the validity of the entrance 
standards and to change them as job require¬ 
ments changed. 

The program was adopted and the work 
started in August 1944. To carry out the initial 
classification all men were given the following 
tests: 

1. Basic Battery (four tests: General Classi¬ 
fication, Reading and Arithmetical Reasoning, 
Mechanical Aptitude, Mechanical Knowledge— 
NavPers 16502, 16512, 16524, and 16533 re¬ 
spectively). 

2. Clerical Aptitude Test (NavPers 16540). 


3. Enlisted Personal Inventory (NavPers 
16842). 

They also filled out a personal history ques¬ 
tionnaire devised by the Division 6 group. By 
November, 1,300 men had been processed. 9 Test 
scores and other information were recorded 
on a special qualification card. This card was 
used because the service records of the majority 
of the men did not contain the standard Navy 
qualification chart properly filled out, and no 
supply of blank forms of the standard chart 
was immediately available. 

After this preliminary testing of the entire 
group on station, only the incoming drafts of 
new men had to be examined. In most cases, 
these men had standard qualification charts in 
good order, so that it was not necessary to ad¬ 
minister the entire battery of tests. On Novem¬ 
ber 20, the task of testing and recording was 
assumed by the Classification and Training 
Officer, Staff, ComSubTrainPac, a position 
created especially to take over the work of the 
Division 6 group. 

In the meantime, in order to eliminate waste 
in the use of training facilities as quickly as 
possible, tentative entrance standards for 
courses were established somewhat arbitrarily. 
Experience, interest, and past training were 
considered as well as the results of aptitude 
tests which were known to have predictive value 
in similar situations. Preliminary studies were 
made correlating test results and questionnaire 
information against grades obtained in the 
various training courses. Because of the small 
number of students in some courses and the 
inadequacy of course grades as criteria, the 
validity of the entrance requirements could be 
established in only a limited fashion. 

When the members of the division group ter¬ 
minated their work at Pearl Harbor in Decem¬ 
ber 1944, responsibility for the classification 
program was taken over by the Classification 
and Training Officer. 


421 Comment 

The move to establish a systematic program 
for assigning men to training courses on the 
basis of their aptitude and experience was a 


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44 


SELECTION OF SUBMARINE PERSONNEL 


long-delayed step forward. Badly needed train- To accomplish the broader objective of select¬ 
ing facilities were being wasted on men who ing the best-qualified men for each training 

had neither the aptitude nor the background course would require a long-range program, 

knowledge to benefit from them. The prelimi- starting with a set of thorough job analyses 
nary entrance standards, although they were and ending with a continuing process of re- 

tentative, served to reduce this wastefulness by validation. In this sense, what was accom- 

eliminating the men who were least qualified, plished at Pearl Harbor was only a beginning. 


RESTRICTED 



Chapter 5 

TRAINING OF SUBMARINE PERSONNEL 


D ivision 6 began to take an active part in 
the training of submarine personnel in the 
late summer of 1943. By then sonar equipment 
developed by the division laboratories was 
in production and was being installed on 
submarines. As with antisubmarine warfare 
[ASW] developments, it was necessary to de¬ 
velop training programs to introduce the new 
equipment. 

The work of organizing programs for labora¬ 
tory developments led to requests for assistance 
in other phases of submarine training. At this 
point, experience gained in the earlier ASW 
work proved a marked asset. Effort was con¬ 
centrated on planning and developing entire 
training programs rather than on fulfilling scat¬ 
tered requests for specific kinds of assistance 
such as construction of trainers or preparation 
of training aids. As a result it was possible, 
particularly in connection with sonar, radar, 
and voice communications training, to carry 
out systematic programs which included the fol¬ 
lowing major steps. 

1. Analysis of training needs to determine 
the number of men to be trained and the knowl¬ 
edge and skills which they were to be given. 

2. Survey of existing training facilities and 
planning of additional facilities so that train¬ 
ing needs could be met. 

3. Planning of course curricula designed to 
satisfy the training needs and to make the most 
effective use of existing facilities. 

4. Training of Navy instructors for the par¬ 
ticular program in which they were to be en¬ 
gaged. 

5. Preparation of achievement tests, both 
objective-type written examinations and meas¬ 
ures of performance. 

6. Preparation of training aids, such as 
manuals for instructors and students, demon¬ 
stration equipment, demonstration and drill 
recordings, films, lantern slides, and charts. 

7. Design and construction of synthetic 
trainers. 

8. Field work by training group representa¬ 
tives. 


A brief account is given below of the assistance 
provided by Division 6 to submarine schools 
and training commands. 

51 SONAR TRAINING PROGRAMS 

Division 6 participation in submarine sonar 
training began when the first units of the new 
JP sonic listening equipment were installed on 
submarines during the summer of 1943. To the 
Columbia University Division of War Research 
[CUDWR] laboratory, which had designed and 
developed JP, fell the task of providing training 
for men who were to operate and maintain the 
equipment. Beginning with this training pro¬ 
gram for JP, Division 6 took an increasingly 
active part in the rapid expansion of submarine 
sonar training. 

sa i JP Training Program 

Initially, JP training was given to the crews 
of individual boats during underway exercises. 
As the production rate of JP gear increased, it 
became necessary to train men more rapidly; 
therefore instruction was given ashore as well 
as underway. 

To implement the training courses, an assort¬ 
ment of training aids was prepared. Suggested 
course outlines and lesson plans were compiled 
in handbook form for instructors. A manual on 
maintenance and trouble-shooting and an op¬ 
erator’s manual, Topside Listening, were writ¬ 
ten and printed for student use. An album of 
phonograph recordings was produced. Phono¬ 
graph playbacks were procured and modified so 
that recordings could be played through the 
JP amplifier, thus enabling the instructor to 
demonstrate use of gain and filter controls. 

A JP amplifier-demonstrator was provided 
for maintenance instruction. It consisted of a 
large wooden mockup of the JP amplifier. A 
blown-up wiring diagram and the actual ampli¬ 
fier parts wired to permit voltage and resistance 
checks were mounted on the demonstrator 
chassis. 


RESTRICTED 


45 


46 


TRAINING OF SUBMARINE PERSONNEL 


JP training kits containing the above equip¬ 
ment as shown in Figure 1, plus standard JP 
amplifiers and miscellaneous small parts of the 
JP gear, were assembled and shipped to sub- 



Figure 1 . Main components of JP training kits. 


marine training activities at the following 
places: New London, Portsmouth, Key West, 
Manitowoc, Hunter’s Point, San Diego, Pearl 
Harbor, and Midway. 

Representatives of the Division 6 training 
group visited each of these bases, started a 
training course, and gave instruction until a 
Navy instructor could be trained. Since Navy 
instructors were not always available the train¬ 
ing group representatives sometimes continued 
to conduct classes for several months. The scope 
of the JP program is indicated by the fact that, 
between November 1943 and March 1945, from 
one to five men were giving full time to JP 
field work. 

512 Assistance to ComSubTrainPac and 
ComSubs7thFleet 

In April 1944, ComSubTrainPac called a con¬ 
ference at Pearl Harbor to discuss plans for 


expanding sonar training in line with the 
growing importance of submarine sonar. Repre¬ 
sentatives of Division 6 were invited to partici¬ 
pate in this conference. It was decided that 
immediate steps should be taken to set up basic 
and refresher courses for sonar operators and 
maintenance men at Pearl Harbor under Com¬ 
SubTrainPac, and a refresher course at Perth, 
Australia, under ComSubs7thFleet. 

The engineering staff of the CUDWR labora¬ 
tory and the BuShips Field Engineering Group 
were called upon to assist ComSubTrainPac in 
planning the layout of a sonar training barge 
and in supervising its construction and the 
installation of equipment. When completed in 
the fall of 1944, this barge became the center 
for all sonar training at Pearl Harbor. 

Meanwhile, Navy instructors had been se¬ 
lected for the Pearl Harbor project and sent 
to New London for special training. In June, 
a four-week course for these instructors was 
started at the CUDWR laboratory. During the 
first two weeks, instruction was given on sub¬ 
marine sonar operation and maintenance, fol¬ 
lowed by underway drill aboard submarines. 
In the last two weeks, emphasis was on effective 
methods of teaching, the use of training aids, 
and the planning of course curricula. Conclud¬ 
ing sessions were devoted to practice teaching 
and to the planning of curricula for the courses 
to be given at Pearl Harbor. 

Members of the New London training group 
accompanied the Navy instructors to Pearl 
Harbor and assisted them in getting the new 
courses started. Classes in sonar operation and 
maintenance began on the barge at Pearl Har¬ 
bor in September 1944. 

An officer and three enlisted men who were 
to give sonar refresher courses at Perth also 
attended the four-week course at New London. 
Training aids and instructional supplies were 
assembled and shipped. Sonar instruction, given 
principally during underway exercises, was 
begun at Perth in September 1944. 

Assistance to ComSubsLant 

In August 1944, a program for basic and 
refresher sonar operator instruction was initi¬ 
ated by ComSubsLant as part of the precom- 


RESTRICTED 














SONAR TRAINING PROGRAMS 


47 


missioning training of new construction crews 
at New London. In addition, brief courses on 
the latest sonar developments were established 
for communications officers and for prospective 
commanding officers. 

A former net tender was obtained by Com- 
SubsLant for conversion into a sonar-radar 
training barge similar to the one being out¬ 
fitted by ComSubTrainPac. The CUDWR labo¬ 
ratory assisted in planning the arrangement of 
training facilities on the barge, supervised the 
remodeling work, designed and manufactured 
special monitoring equipment, and aided in the 
installation of standard equipment modified for 
training purposes. 18 

The CUDWR training group, in collabora¬ 
tion with Navy personnel, developed an in¬ 
tegrated training program designed to make 
full use of all facilities. A two-week course was 
planned, the first to include classroom instruc¬ 
tion and procedure drill on standard sonar 
equipment installed on the piers at the Sub¬ 
marine Base, the second week to be spent in 
advanced instruction on the sonar-radar barge 
anchored in Long Island Sound. For the barge 
training, a target boat was equipped to play 




Figure 2. Group listening teacher in operation. 


recordings of various ship sounds through an 
underwater projector. 

Facilities on the barge for sonar instruction 
included two rooms containing the same JP 
and WCA equipment as the submarine forward 
torpedo rooms, two WCA drill rooms, two JP 
drill rooms, a classroom, and a lookout station. 


An instructor’s control console was provided 
for each of the JP drill rooms (see Figure 2). 
From the console one instructor could monitor 
several JP stations. Other later equipments 
were installed on the barge as they became 
available. 

Sonar classes were started on the barge in 
January 1945; instruction ashore had begun 
somewhat earlier. 


51-4 Operator and Officer Training at 
WCSS 

In October 1944, a committee appointed by 
COMINCH made a survey of submarine sonar 
training at New London. On the basis of this 
survey the committee recommended that a basic 
course for submarine sonar operators be es¬ 
tablished at the West Coast Sound School, San 
Diego [WCSS]. It also recommended that 20 
per cent of the officer graduates of the Sub¬ 
marine School, New London, be sent to San 
Diego for special training in submarine sonar 
operation and tactics. Both officers and men 
were to attend the Submarine School radar op¬ 
erator’s course before going to San Diego. 

The adoption of this plan gave an opportunity 
for the development of entirely new programs 
of sonar operator and officer instruction. Repre¬ 
sentatives of the CUDWR and UCDWR train¬ 
ing groups collaborated with the instructional 
staff of WCSS in planning the new courses. 
Lesson plans were made for lectures and drill 
sessions; tentative lectures were written; ob¬ 
jective-type written examinations and perform¬ 
ance check lists were prepared; training aids 
were systematically assembled. 

Two new synthetic trainers, the group listen¬ 
ing teacher and the sound recognition group 
trainer [SRGT], were made ready by the 
UCDWR laboratory. The group listening 
teacher (see Figure 3) provided an automatic 
problem generator and a central console for 
monitoring 8 JP, 5 WCA, and 4 WEB equip¬ 
ments each enclosed in a sound-treated booth. 
Behind this quickly constructed group listen¬ 
ing teacher was a long history of development 
by the UCDWR laboratory. Originally, primary 
listening teachers somewhat similar to the 


RESTRICTED 








48 


TRAINING OF SUBMARINE PERSONNEL 




Figure 3. Group listening teacher. 


RESTRICTED 































SONAR TRAINING PROGRAMS 


49 


primary bearing teachers had been provided 
in quantity, but these were useful only for in¬ 
struction in elementary procedures. An experi¬ 
mental model of an advanced listening teacher 
had been completed during the summer of 1944. 
The unique problem generator of this device 
was modified for use with the group listening 
teacher. 

The sound recognition group trainer was a 
direct adaptation of the echo recognition group 
trainer [ERGT] used in ASW operator train¬ 
ing. Recordings of sounds picked up over sub¬ 
marine listening gear were made into a series 
of drills, graded in difficulty. Each student’s 
responses to the drill items were recorded on a 
web of paper at the central console from which 
the instructor directed the drills. Tests in turn 
count estimation, faint contact detection, target 
identification, and other auditory discrimina¬ 
tions provided reliable objective scores of stu¬ 
dent performance in this essential phase of 
sonar operation. The SRGT drills and tests 
formed an important part of the training course 
for submarine sonar operators. 

Instruction in submarine sonar was started 
at WCSS in November 1944. The course for 
operators was four weeks in length, three weeks 
ashore and one week underway on submarines 
which were operating with the ASW training 
vessels. The officers’ course was limited to two 
weeks ashore. At a later date the operators’ 
course was extended to five week^ 

Sonar Maintenance Training, 
Submarine School 

In line with the recommendations of the 
COMINCH committee work was also begun on 
the establishment of a maintenance training 
course at New London. As a first step, an officer 
experienced in ASW sonar maintenance train¬ 
ing was transferred to New London from the 
Fleet Sound School, Key West [FSS]. The 
CUDWR training group worked with this offi¬ 
cer in planning training facilities, installing 
equipment, and planning a curriculum for the 
new course. Individual instructors were also 
given assistance in the preparation of lesson 
plans. 


In order to simulate equipment casualties, 
trouble injectors were designed and built by 
the CUDWR laboratory. By throwing appropri¬ 
ate switches instructors were able to set up a 
series of trouble-shooting problems. 

The maintenance course was four weeks in 
length; it was an advanced course designed for 
radio technicians who already had basic elec¬ 
tronics training. Emphasis was placed on 
laboratory work, each student spending ap¬ 
proximately 50 per cent of his time working 



Figure 4. Standard sonar equipment. 


with standard sonar equipment (see Figure 4). 
Maintenance instruction was started in Janu¬ 
ary 1945. 


516 JT, NLM, TDM, DCDI, and DCRE 
Training 

In addition to giving assistance in the es¬ 
tablishment of complete sonar training courses, 
the Division 6 training group, during 1944 and 
1945, prepared instructional material for a 
number of sonar equipments developed by di¬ 
vision laboratories. Instruction in use and main¬ 
tenance of these equipments was added to 
the curricula of existing courses. In each in¬ 
stance, instruction books and other training 
aids were prepared for distribution with the 
first production units of the equipment. 

For JT sonar, operator and maintenance 


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50 


TRAINING OF SUBMARINE PERSONNEL 


manuals, lantern slides, and lecture outlines 
were prepared. No new phonograph recordings 
were needed, since the sounds heard over JT 
and JP were virtually identical. 

For the Noise Level Monitor [NLM], a syn¬ 
thetic trainer (see Figure 5) was developed 
to permit separate recordings of submarine 


Lantern slides and lesson plans for classroom 
use were prepared. 

Throughout 1944 and early 1945, lectures on 
all of these new laboratory developments were 
given periodically by the CUDWR staff to pros¬ 
pective commanding officers, communications 
officers, and Navy instructors. 



Figure 5. Noise level monitor components. 


machinery sounds and of background water 
noise to be played through a control panel into 
a monitor unit attached to a JP amplifier. At 
the control panel relative levels could be ad¬ 
justed to simulate the sounds heard over each 
of the four NLM hydrophones aboard a subma¬ 
rine. Operation on this trainer closely simulated 
the conditions of using NLM at sea. Other 
instructional materials included a set of re¬ 
cordings to be used with the trainer, a wall 
chart, manuals for operators and maintenance 
men, and lesson plans for instructors. , 

For TDM equipment, the range recorder 
teacher [QFL] was modified by the substitu¬ 
tion of standard bearing recorders as used in 
the torpedo detection modification aboard sub¬ 
marines. Five or more recorders were attached 
to a single central unit. Recordings of torpedo 
sounds produced characteristic recorder traces 
as well as the accompanying sounds. The device 
was given the Navy designation QFM. Instruc¬ 
tion manuals for ,TDM operators and mainte¬ 
nance men were also prepared. 

DCDI and DCRE required no operating in¬ 
structions. Booklets explaining the use of these 
devices and maintenance manuals were written. 


5,1,7 General Sonar Training Aids 

Several additional training aids which have 
not been mentioned played a part in the sonar 
training programs. The Submarine Sonar Op¬ 
erator’s Manual (NavPers 16167), written by 
the training group, was printed and distributed 
by BuPersg to all training activities and all 
submarines. This manual (see Figure 6) pre¬ 
sented for the first time standardized and offi¬ 
cially accepted doctrines for sonic and super¬ 
sonic searching and tracking and for single-ping 
echo ranging. 

Paralleling the JP series of recordings, 
demonstration and drill recordings for WCA 
supersonic listening were developed by the 
training group and distributed in album form 
by BuPers. A set of experimental target-dis¬ 
crimination drill and test recordings, in which 
the student was required to pick out the desig¬ 
nated target sound from other similar and con¬ 
fusing sounds, was completed and copies were 
made for experimental use at New London and 
San Diego. 

A slide film on “Fundamentals of Sound” was 
produced for the Submarine School, New Lon- 


RESTRICTED 













VOICE COMMUNICATIONS PROGRAM 


51 


don. The film consisted of two 15-minute reels, 
each accompanied by a sound recording. Film 
and recordings were distributed by BuAer. 


ous minor training aids were also developed. 

The radar operator course was started in 
December 1944. A member of the training 


This is the way 



CONFIDENTIAL 


U 


the JP amplifier works 


1st amplifier stage receives the incoming elec* 
trie current from the hydrophone and makes 
it stronger. 

2nd amplifier stage makes this amplified cur¬ 
rent still stronger. 


Bass-boost filter weakens 
frequencies above 1500 
cycles, making the low fre¬ 
quencies seem stronger. 


3000-cycle filter weakens 
frequencies below 3000 
cycles, making the higher 
frequencies seem stronger. 


500-cycle filter cuts out fre¬ 
quencies below 500 cycles: 
it weakens frequencies from 
500 to 2500 cycles, making 
the higher frequencies seem 
stronger. 

6000-cycle filter makes 6000 
cycles stand out by weaken¬ 
ing frequencies lower and 
higher than this. 


Flat filter passes all fre- 
quencies equally well. 


3rd amplifier stage makes the filtered current 
stronger. How much stronger is determined 
by the volume-control setting. 


4th amplifier stage makes this amplified cur¬ 
rent still stronger. 


Prop-count detector 

changes the current so that 
the propeller beats stand out. 

Output amplifier stage makes the current 
strong enough for the headphones. 


Transformer changes the 
current so that the loud¬ 
speaker can handle it. 
Loudspeaker changes the 
electrical current into sound. 


Heodphones change the 
electrical current into sound. 

IT 


Amplifier strengthens a small 
portion of the current. How 
much it is strengthened is 
determined by the indicator- 
control setting. 

Filter cuts out all frequencies 
below 6000. 

tectifier changes the current 
so that the indicator can 
handle it. 

Magic eye indicator lets the 
operator's eye see what his 
ears hear. The eye closes 
when current is strongest. 

CONFIDENTIAL 


Figure 6. Pages from Submarine Sonar Operator’s Manual. 


52 RADAR TRAINING PROGRAM 

In October 1944, CUDWR received a request 
from the Submarine School at New London for 
assistance in establishing a course for sub¬ 
marine radar operators. The CUDWR training 
group in turn asked the Applied Psychology 
Panel, NDRC, to collaborate in fulfilling this 
request, since members of the Panel’s project 
SC-70, NS-146, had had considerable experience 
in planning training courses for surface craft 
radar operators. 

Together the two groups planned the course 
curriculum, developed lesson plans, outlined drill 
schedules, and trained the Navy instructors as¬ 
signed to the school. They worked with the 
instructional staff in the preparation of lec¬ 
tures, objective-type examinations, and check 
lists for evaluating student performance. Vari- 


group continued to work with the course in¬ 
structors for several months. The curriculum 
was revised to meet deficiencies which ap¬ 
peared, additional work was done on perform¬ 
ance tests in an effort to obtain accurate meas¬ 
ures of operating skill, and a preliminary 
instruction book on fundamentals of radar was 
written. 


53 VOICE COMMUNICATIONS PROGRAM 

In April 1944, the CUDWR training group 
was asked by ComSubsLant to assist in the 
development of a training program designed 
to improve voice communications on subma¬ 
rines. 

The aid of two other NDRC groups which 
were experienced in the field of voice com- 


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52 


TRAINING OF SUBMARINE PERSONNEL 


munications was obtained. These groups were 
the Psycho-Acoustic Laboratory, Harvard Uni¬ 
versity, Division 17, Section 17.3, and Project 
N-109 Psychological Corporation, Applied Psy¬ 
chology Panel. 

In order to best fulfill the request made 
by ComSubsLant, a two-fold program was 
planned: first, the standardization of phrase¬ 
ology and procedures used in voice communi¬ 
cation; second, the establishment of training 
courses for officers and men. 


Standardized Phraseology 

To accomplish the first part of this program, 
a catalogue was made of alternative forms of 
all commands and reports in common use. These 
were arranged according to the ship’s opera¬ 
tions involved. Experimental tests were then 
conducted to determine the relative intelligi¬ 
bility of the alternative forms; these tests were 
made using sound-powered telephone equip¬ 
ment in the presence of masking noise designed 
to reproduce the noise ordinarily present dur¬ 
ing operations on board a submarine. On the 
basis of the experimental tests and conformity 
with submarine usage, detailed uniform voice 
procedures and specific wordings for all im¬ 
portant submarine commands were prepared. 
These were submitted for criticism to officers 
throughout the submarine service and, with 
slight revisions, were compiled in a booklet en¬ 
titled Standard Submarine Phraseology (see 
Figure 7), copies of which were distributed by 
ComSubsLant to all submarine activities. 


Training Courses 

The development of the training program 
proceeded concurrently with the work on stand¬ 
ardization of phraseology and procedures. A 
basic course for enlisted men and officers was 
outlined, a training room was planned, stand¬ 
ard submarine communication equipment was 
procured, additional equipment needed for the 
training room was designed and constructed, 
and various training aids were prepared. The 
first training room (see Figure 8) was set up 


and a basic course was started in May 1944 at 
the New Construction Training School, New 
London. 

In June 1944, a program of training at three 
levels was approved by ComSubsLant. This pro- 


CRUISING SURFACED 


These examples cover the miscellaneous orders used in the general operation of 
the ship Bridge orders over XJA are usually relayed by the conning tower 


Bridge 

Control 

Bridge 

Conning tower 
Bridge 


Ot-er Orders and reports 

XJA Forward room, rig out the bendix (pit) log. 

7MC Bridge, permission to test the bow planes. 

7MC Control, cut in the bridge gyro-repeater at\d the bridge 
rudder-angle indicator. 

7MC Control, notify the Captain we changed course to"Bne eight 
ze-ro at twenty-one nineteen, when log read seven two and 
a half. 

XJA Maneuvering, start a battery charge on two main engines. 

Maneuvering acknowledges by stating which engines are being 


Bridge XJA Maneuvering, carry a one hundred amp float with thuh-ree 

Bridge XJA Maneuvering, get a gravity reading. 

A typical report would be: "Conning tower, gravity forward 
twelve fifty, temperature one eighteen. Gravity aft twelve forty 


Bridge 

7MC 

Bridge 

7MC 

Bridge 

7MC 

Bridge 

XJA 

Control 

7MC 

Bridge 

XJA 

Bridge or 

7MC 


conning cower 


Control, darken the control room. 

Control, dump garbage through the conning tower hatch. 
Control, blow all sanitary tanks. 

Forward engine room, how are your bilges? 

Bridge, keep clear of antenna. We are transmitting. 

Battery aft, gunner’s mate to the bridge. 

Control, reading on the DRAI. 


RESTRICTED 


II 


Figure 7. Page from Standard Submarine 
Phraseology. 


gram included a basic course in the funda¬ 
mentals of telephone talking, an intermediate 
course emphasizing the procedures and phrase¬ 
ology for each station, and an advanced course 
covering coordination of voice communications 
by the combat team. 

In September 1944, COMINCH approved the 
extension of the Voice Communications Train¬ 
ing Program to six other submarine training 
activities in addition to the New Construction 
Training School and Submarine School, New 
London. These were Portsmouth, San Diego, 
Hunter’s Point, Mare Island, Pearl Harbor, and 
Midway. 

Officers who had had experience in teaching 
speech were obtained to serve as head instruc¬ 
tors at each of the six places. These officers and 
a group of enlisted men were trained at New 


RESTRICTED 






VOICE COMMUNICATIONS PROGRAM 


53 


London by the NDRC groups and the Medical 
Research Department, the latter having been 
put in charge of all voice communication train¬ 
ing at the Submarine Base, New London. 


organization book), a brief description of sub¬ 
marine voice communication circuits, recom¬ 
mendations for manning stations, rules for 
correct operation of equipment, and outline of 



INSTRUCTION 
W BOOKS 


REGORDER 


INTERPHONE 
TRAINING UNIT 

wrim x 
lMR i 


SOUND-POWERED PHONES 
PLAYBACK 




Figure 8. Training room equipment. 


5-3-3 Training Aids 

A number of training aids and devices were 
prepared for use in the voice communication 
instruction. These included the following: 

1. Standard Telephone Talkers’ Manual, a 
basic text on submarine voice communication 
procedures. 

2. Standard Submarine Phraseology, a book¬ 
let giving voice procedures and phraseology 
recommended as standard for all submarine 
voice communication. 

3. Ship’s Organization Chapter on Voice 
Communications (to be inserted in each ship’s 


standard voice procedures. 

4. Instructor’s Handbook for Basic Course, 
an outline of a basic course for officers and 
men, instructions for installation and mainte¬ 
nance of equipment in training rooms, drill 
material, record forms, and lecture notes. 

5. Wall charts, a list of “Seven Rules for 
Telephone Talking” and “Pronunciation of 
Numerals.” 

6. Submarine telephone talker training rec¬ 
ord, a phonograph recording illustrating cor¬ 
rect and incorrect voice communications during 
battle circuit drill. 

7. Training interphone, an instrument de- 


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54 


TRAINING OF SUBMARINE PERSONNEL 


signed by the Psycho-Acoustic Laboratory for 
use with classroom drill circuits. The inter¬ 
phone included a noise generator, a meter for 
measuring level of speech, and a filter for dis¬ 
torting speech. 

8. Switch panel, a central control mechanism 
for the instructor monitoring drill circuits. 

Kits for completely equipping the training 
rooms were assembled at New London and dis¬ 
tributed to the places where training courses 
were to be established. NDRC personnel as¬ 
sisted in the installation of equipment in the 
voice communication training rooms at New 
London, Portsmouth, and Pearl Harbor. 


54 SUBMARINE BATHYTHERMOGRAPH 
PROGRAM 

Bathythermographs [BT] were first installed 
on submarines in February 1942. From that 
time until the end of Division 6 activities in 
1945, members of the Woods Hole Oceano¬ 
graphic Institution [WHOI] and of the Univer¬ 
sity of California Division of War Research 
[UCDWR] assisted in training submarine per¬ 
sonnel who used and maintained the BT equip¬ 
ment. This assistance was principally of two 
kinds, field instruction and preparation of train¬ 
ing aids. 


Instruction in the Field 

At the start, assistance in submarine BT 
training was given incidentally by WHOI rep¬ 
resentatives who supervised installations of BT 
equipment. In July 1943, this assistance was 
formalized at the request of BuShips a and 
WHOI representatives were sent to the new 
construction training activities at New Lon¬ 
don, Portsmouth, and Manitowoc. They con¬ 
ducted general lectures to introduce the BT to 
large groups of submarine officers and men, 
gave intensive training to small groups of com- 


a The training activities of WHOI from this date on 
were supported by a direct contract between WHOI 
and BuShips. The work is mentioned here, however, to 
complete the picture of submarine bathythermograph 
training. 


munications and diving officers ashore, and 
supervised instruction of officers during tests 
at sea. 

In May 1944, a WHOI representative visited 
the submarine commands at San Diego, San 
Francisco, Pearl Harbor, and Midway. As a 
result of this survey, a WHOI representative 
was immediately assigned to ComSubTrainPac 
for training and field engineering work. A Navy 
officer, trained in use and maintenance of the 
submarine BT, was assigned to similar duties 
with ComSubs7thFleet at Perth, Australia. 

Formal participation of UCDWR in sub¬ 
marine BT field training began in May 1944, 
when the Office of the Coordinator of Research 
and Development requested the establishment 
of a much expanded program in the application 
of oceanography to subsurface warfare. It was 
urged that additional civilian field representa¬ 
tives be furnished to assist submarine training 
commands in the Pacific. 

Three men, trained in oceanography and in 
the installation, operation, and maintenance of 
the submarine bathythermograph, were fur¬ 
nished by UCDWR. From October 1944 until 
September 1945, these men gave instruction 
at various Pacific submarine training activities 
—Mare Island, San Diego, Pearl Harbor, and 
Guam. In the meantime, WHOI representatives 
continued to give BT instruction at submarine 
bases on the Atlantic Coast. 

5 ' 4 ' 2 Training Aids 

In March 1943, at the request of the Office 
of the Coordinator of Research and Develop¬ 
ment, WHOI and UCDWR jointly undertook 
the preparation of instruction manuals on the 
use of oceanographic data in relation to sub¬ 
marine warfare. By July they had completed 
the Use of Submarine Bathythermograph Ob¬ 
servation (NavShips 943-F), which was printed 
by BuShips and widely distributed throughout 
the submarine force. In February 1944, a revi¬ 
sion of the rules for predicting maximum sound 
ranges was finished, followed in March by a 
supplement to NavShips 943-F, Use of the 
Bathythermograph as an Aid in Diving Opera¬ 
tions (NavShips 900,018). Both of these were 
published and distributed by BuShips. 


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SUBMARINE BATHYTHERMOGRAPH PROGRAM 


55 


In May 1944, as part of the expanded pro¬ 
gram in the application of oceanography to sub¬ 
surface warfare, UCDWR undertook the revi¬ 
sion and supplementation of all existing BT 
instructional material. New material resulting 
from oceanographic research was added to that 
already published, and the whole presented in a 
form to insure better understanding of its oper¬ 
ational significance. 

A new edition of Use of Submarine Bathy¬ 
thermograph Observations (NavShips 900,069) 
was planned. It was to be issued in seven sec¬ 
tions in a looseleaf binder, permitting later 
replacements and supplements. By August 1945, 
six of the seven sections had been completed; 
four had been printed and distributed by 
BuShips. A less technical pamphlet, The Sea 
for Submarines (NavShips 900,018) had also 
been written and distributed by this time. 


from the CUDWR training group. The Refer¬ 
ence Handbook for Submarine Bathythermo¬ 
graph Field Engineers was issued to all BT in¬ 
structors in November 1944. 


5 ' 4 ’ 3 Devices 

Two submarine BT training devices were 
built by the UCDWR laboratory late in 1944. 
For SubRon 45, San Diego, the laboratory con¬ 
structed one unit of a BT simulator to be at¬ 
tached to the Askania diving trainer. This 
attachment permitted simulated changes in 
buoyancy to affect diving operations on the 
trainer much as they would be influenced by 
temperature gradients at sea. A similar device 
was later procured by the Navy on direct con¬ 
tract. For WCSS, the laboratory built a class- 



Figure 9. The periscope trainer. The trainer is shown at the left, and at the right is a representative 
field of view as seen in low power. 


Meanwhile WHOI had prepared two publica¬ 
tions for BT instructors. The first, an informal 
pamphlet, Lecture Notes on Use of Submarine 
Bathythermograph, was issued in January 1944. 
It was revised in 1945, with editorial assistance 


room demonstrator. This consisted of a stand¬ 
ard submarine BT with auxiliary attachments 
which enabled the instructor to reproduce any 
desired BT record by applying suitable changes 
in temperature. 


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56 


TRAINING OF SUBMARINE PERSONNEL 


5 5 WORK DONE ON SPECIAL REQUEST 

A number of devices and training aids were 
produced by the CUDWR laboratory to fill spe¬ 
cific requests of the Submarine School, New 
London. 

The periscope trainer was designed to give 
officers elementary practice in ship recognition, 
judgment of angle-on-the-bow, and estimation 
of range by telemeter or stadimeter. The trainer 
had the general form and all of the standard 
controls of the lower part of a Mark IV peri¬ 
scope. Replacing the top of the periscope was 
a circular holder in which could be inserted 
film strips showing target ships at various 
ranges and angles-on-the-bow (see Figure 9). 
Simplified recognition charts were attached. 
The instrument could be used for self-instruc¬ 
tion. After identifying the ship and estimating 
its angle-on-the-bow and range, the student 
could check the correctness of his answers by 
tilting the vertical sweep in low power until 
an answer box above the ship image became 
visible. Six periscope trainers were built at the 
laboratory and shipped early in 1945 to various 
Navy activities. The Navy later let a contract 
for the manufacture of 25 additional units. 

Extensive modifications were made on the 
Mark I attack teacher at the Submarine School. 
In place of the single manually controlled target 
ship of the original model, the redesign per¬ 
mitted the use of five to seven target and screen¬ 
ing ships automatically controlled by a modified 
Mark I TDC. A repeater unit which showed 
own-submarine’s course and speed was installed 
in the conning tower. Another repeater unit in 
the classroom showed relative bearing, target 


speed, range, and angle-on-the-bow. Six addi¬ 
tional modification units were built at the lab¬ 
oratory in 1944 and installed on attack teachers 
at other submarine bases. A sound injector to 
feed automatically controlled target propeller 
noise into the sound stack was designed as an 
adjunct to the attack teacher modification. One 
unit of the injector was installed at the Sub¬ 
marine School in the spring of 1945. 

Five slide films for instruction in estimating 
angle-on-the-bow were made in 1944. Prints 
were procured and distributed by BuAer. 

Negatives of 248 lantern slides for classroom 
use in the various departments of the Sub¬ 
marine School were prepared by the training 
group and turned over to BuAer for final proc¬ 
essing. The majority of the slides were repro¬ 
ductions of wall charts and of diagrams from 
instruction books. 

A method of making lantern slides with mov¬ 
able dials was developed and employed in the 
construction of three types of animated slides 
for teaching relative bearings, search proce¬ 
dures, and the use of the Is-Was. Seven units of 
each were furnished by CUDWR. 

A large-scale model of the Mark VIII tor¬ 
pedo angle solver was constructed as a class¬ 
room aid for the Submarine School. 


56 SUBMARINE TRAINING AIDS 

Phonograph recordings, slides and films, and 
classroom teaching devices prepared by Divi¬ 
sion 6 are listed in Appendix III. A list of in¬ 
struction books may be found in the bibliog¬ 
raphy. 


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Chapter 6 

TRAINERS FOR ANTISUBMARINE WARFARE SONAR OPERATORS 


I N AN EARLY report of the NDRC Committee 
on the Selection and Training of Sound 
Operators, the need was expressed for devices 
which would afford training in the various con¬ 
stituent skills required of sonarmen. In the case 
of surface craft sonarmen, the ability to keep 
the QC projector directed on a moving target 
and accurately report its bearings is probably 
of first importance. It is essential that this 
routine become practically automatic, and yet 
it is one of the most difficult to master. Special 
attention was therefore given to the develop¬ 
ment of trainers providing drills in echo-rang¬ 
ing search and target-bearing reporting. 

The first trainer which was designed and de¬ 
veloped as part of the program for the training 
of surface craft sonarmen was the bearing 
teacher. This device was so complex in construc¬ 
tion, however, that production in quantity was 
too slow. Because of this disadvantage it was 
necessary to develop a more elementary type 
which could be produced quickly in quantity. 
This later design was known as the primary 
bearing teacher [PBT]. The original trainer 
was then designated the advanced bearing 
teacher [ABT]. Later, after the bearing devia¬ 
tion indicator [BDI] had been perfected and put 
into operational use, an auxiliary BDI training 
unit (OTE-8) for attachment to the ABT was 
designed. A more compact version of the PBT, 
small enough to be carried by hand aboard ship 
or at advance posts where classroom facilities 
might have to be improvised, was likewise de¬ 
veloped. This was designated the midget bearing 
demonstrator [MBD]. 

All these early trainers served to train only 
one student at a time. This was a serious draw¬ 
back, since it tied up the time of the instructor 
as well as the trainer. In the later phases of 


the training program, the principles of the in¬ 
dividual trainers were adapted and applied to a 
series of group trainers, in which a number of 
student practice stations could be directed and 
monitored by a single instructor simultane¬ 
ously. Since these group trainers were the most 
effective and economical in terms of time of all 
the elementary training devices, and since they 
would undoubtedly be the point of departure 
for any future elementary training program, 
they are described in some detail here. The 
earlier, individual trainers are not covered, but 
the interested reader will find references to 
microfilmed material on all of them in the bib¬ 
liography for this chapter. The advanced bear¬ 
ing teacher in particular did yeoman service in 
refresher drills aboard training ships where 
there was not space enough for larger installa¬ 
tions. 

One of the first and simplest of the group 
trainers developed is the echo recognition group 
trainer [ERGT], used for the sole purpose of 
teaching discrimination among underwater 
sounds. This device is described first. Operator 
training equipment, Models 2 and 10 [OTE-2 
and OTE-IO], is then discussed. Although 
OTE-2 is an individual operator trainer, it is 
included because it forms the basis for the pro¬ 
posed OTE-IO, which would provide target 
bearing, range, and doppler inputs to five or 
more sonar practice stacks simultaneously. An 
account is then given of the BDI trainer, de¬ 
veloped to serve as an adjunct to either ABT 
or the Sangamo attack teacher and later 
adapted to and incorporated in the group oper¬ 
ator trainer. Proceeding in order of increasing 
complexity, the group operator trainer is de¬ 
scribed last. 


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57 


58 


TRAINERS FOR ANTISUBMARINE WARFARE SONAR OPERATORS 



/ DOPW'-fc* 

OGPPLtK H 

-»««« 

(*O0W* TE 


OOPPUER tow, 


SUB. 

SUSHt 


Figure 1. Station key for echo recognition group 
trainer. 



phonograph recordings of actual sea echoes and 
reverberations, student stations with manually 
operated station keys, and an instructor’s sta¬ 
tion. The station key at each student post has 
seven positions ichich permit the student to 
report his findings to an echo recognition mon¬ 
itor recorder at the instructor’s station. This 
echo recognition monitor recorder consists of 
a group of station keys and one recorder. The 
latter may be the Model II type A, shown on 
the left of Figure 2, or a combination of type A 
and type B. The instructor follows the visual 
reports as they show on the recorder and thus 
is enabled to check continuously on each man’s 
judgment of the echoes and to point out the 
errors made. This training device was devel¬ 
oped by UCDWR. 


61 STATION KEY DESCRIPTION 


The station key has seven positions, as shown 
in Figure 1. Each key is connected to three styli 
in the monitor recorder and to the two voltage 
sources indicated in Figure 3. Position X is the 



Figure 3. Schematic diagram of marking circuit. 


Figure 2. Echo recognition monitor recorder 
(combination of type A and B units). 

Echo Recognition Group Trainer 

The echo recognition group trainer [ ERGT ] 
is used to drill and test students, simultaneously 
at numerous individual stations, in analysis 
of underwater sounds. The equipment includes 


normal or “no echo” position, at which all three 
styli have zero voltage and do not operate. 

When the station key is moved to position 1, 
a steady d-c voltage is applied to stylus 1 and a 
solid mark is recorded as shown at A. When the 
station key is moved to position 6, an inter¬ 
rupted d-c voltage is applied to styli 1, 2, and 
3, thus marking the recorder paper as shown 


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ELECTRIC CIRCUITS 


59 


at F . The type of markings recorded at the in¬ 
termediate key positions 2, 3, 4, and 5 are like¬ 
wise illustrated in the figure. 

The six marking positions of the station key 
may be used as desired to make any of six dif¬ 
ferently indicated reports to the instructor. As 
Figure 1 shows, double meanings were assigned 
to the three lower positions. In any given exer¬ 
cise, the character of the recorded material and 
the sequence of reporting determined which of 
the double meanings were used. 

The station key is operated by moving the 
handle. The handle in turn moves the white 
target spot fastened through the plate to the key 
shaft. When the handle is released, the target 
spot returns to the “no echo” position. 


62 TANK AND PAPER DRIVE ASSEMBLY 

The tank and paper drive assembly is the 
standard design used in the Sangamo range 
recorder, except that its length has been ex¬ 
tended by setting the drive roll farther from 
the tank. 

The a-c paper drive motor operates at ap¬ 
proximately 1,750 rpm through two sets of 
reduction gears to drive the paper roll at the 
front of the recorder. The motor and high-speed 
reduction gears are mounted on Lord mounts 
to reduce motor noises. This set of reduction 
gears connects with a flexible coupling to the 
low-speed set of reduction gears. The paper 
drive roll causes the recording paper to travel 
15 Vsj in. per minute. At the right end of the 
drive roll (see Figure 4) is an additional spring 
coupling which drives the Type B unit if the 
latter is attached. 

The styli are mounted in a phenolic bar, each 
soldered tightly in one of the metal tubes. A set 
screw holds each stylus in place and provides a 
means of adjustment to give uniform paper 
pressure and uniform marking. (The intensity 
of marking on the paper depends somewhat on 
stylus pressure.) The stylus bar is held in place 
on the tank assembly by steel pins which also 
serve as the axis of rotation for the stylus bar. 
The push-bar assembly operates on the arm to 
hold proper stylus pressure when the recorder 
tank is closed. However, when the tank is 


opened to change paper, the push bar slides back 
so that the stylus assembly can be tilted to raise 
the styli. 



Figure 4. Type A monitor recorder, interior 
view. 


6 3 ELECTRIC CIRCUITS 

Steady and interrupted d-c voltages are sup¬ 
plied to each station through the Cannon plug 
terminal. These voltages are returned from 
each station key to the marking styli. The value 
of the marking voltage may be adjusted by the 
sensitivity potentiometer, R-103, which varies 
the a-c voltage supplied to the rectifier unit. 
Three circuits to operate the monitor recorder 
include (1) a step-down transformer which 
delivers 6.3 volts of alternating current to two 
selenium rectifiers, thus providing the d-c power 
to the styli for marking (the three styli ter¬ 
minals are connected to the key contacts 
through 1,000-ohm resistors) ; (2) a circuit 
which supplies power to a 110-volt, 60-c motor 
that may be silently turned off or on by means 
of a lever-operated microswitch; and (3) a 
power circuit which furnishes 110 volts to the 
electric heaters for the plates which dry the 
paper. 


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60 


TRAINERS FOR ANTISUBMARINE WARFARE SONAR OPERATORS 




Figure 5. Inserting program cam in mechanical 
unit. 


Operator Training Equipment — 
Models 2 and 10 

Operator training equipment, model 2 
(OTE-2) is a device which provides target in¬ 
formation inputs to a sonar stack to aid in 
training an individual sonar operator to “hold” 
a target throughout an attack run. The pro¬ 
posed OTE-10 provides similar inputs to five or 
more stacks simultaneously, thus requiring only 
one instructor for several operators. The signals 
are generated by an electronic unit and con¬ 
trolled in range, doppler, and bearing effects by 
program records inserted in a mechanical unit. 
Readings on the front panel of the mechanical 
unit indicate student performance. Both de¬ 
vices were developed by HUSL. 

64 INTRODUCTION 

Operator training equipment in general was 
an outgrowth of the attempt to supply artificial 
signals for use in testing sonar gear. Such test 
signals, as they were perfected, were quickly 
applied in the training field, since they con¬ 
stituted a means of duplicating certain opera¬ 
tional conditions in the classroom. 

65 TECHNICAL DEVELOPMENT 

In the early phases of the development of 
artificial signals for testing purposes, various 
methods of producing signals were tried. The 
first was an attempt to play phonographically 


recorded reverberation with an electric pickup 
and then to feed the signals through proper 
circuits into sonar gear under test. This method 
proved unsatisfactory because of the difficulty 
in recording and reproducing the high frequen¬ 
cies found in reverberation. An attempt was 
then made to generate an accurate simulation 
of the reverberation signal by electronic means. 
To do this a noise generator was developed in 
which the noise signal produced frequency 
modulation of an oscillator whose output was 
fed to a receiver in such a manner that the 
signal intensity decreased with time. Since this 
effect was the reverse of normal time-varied 
gain [TVG], in which the gain increases with 
time, it was given the name of inverse time- 
varied gain. When the proper bandwidths were 
determined, this arrangement gave a fair imi¬ 
tation of the reverberation signal. Simple key¬ 
ing circuits were then developed by means of 
which ping and echo signals could be injected 
when desired. 

It was then suggested that phase modulation 
might give more accurate reverberation simula¬ 
tion, and two simultaneous lobe comparison 
[SLC] demonstration units were developed to 
provide phase-modulated echo and reverbera¬ 
tion signals. These devices were equipped with 
manual control of the phase shift of the echo to 
give left-right indications, and with electronic 
control of the random phase variation of rever¬ 
beration. 

Later an arrangement of projector simulator 
coils was incorporated as an improvement in 
the SLC demonstration unit. These coils had 
been developed as part of the artificial projector 
(see Chapter 11) but proved valuable in a 
number of other applications involving phase 
modulation, including several OTE equipments 
in addition to the models discussed in this sec¬ 
tion. The projector simulator coils comprised 
essentially an exciter coil, fed with keyed signal 
current, that was moved manually in accordance 
with the bearing deviation, over three second¬ 
ary coils. The output of these coils was properly 
phase- and amplitude-modulated to simulate the 
output of a projector and could be fed directly 
into a BDI to give indications just like those 
obtained from an actual projector operating 
under service conditions. At this stage of the 


RESTRICTED 



GENERAL DESCRIPTION OF OTE-2 


61 


OTE-2 development, the coils were used only 
for echo generation, since reverberation and 
noise were still being provided electronically. 

The next step was to use projector simulator 
coils to produce the reverberation as well as 
the echo, since electronically generated rever¬ 
beration was found to produce an unsatisfactory 
image on the BDI screen. In this form, the 
OTE-2 was an automatic motor-driven attack 
simulator that would deliver reverberation sig¬ 
nals and echo signals similar to those obtained 
in actual service for time variation of target 
range, bearing, and echo doppler. 

In the device in its final form, it was planned 
to control the variation of echo and rever¬ 
beration by means of rotary program cams. 
Rectilinear cams were substituted, however, be¬ 
cause they made it possible to use easily change¬ 
able “program records” by means of which 
signals could be supplied simulating those of 
previous actual attacks on submarines, and also 
to include in the device a simple mechanism to 
record permanently the operator’s performance 
in following the ship’s course during the attack. 

When operated aboard ship at dockside it 
was found that the reverberation-producing 
part of OTE-2 could be turned off and the 
natural reverberation used quite satisfactorily. 
When the ship was under way, however, the 
problem of locking in echo doppler with the 
reverberation proved very troublesome. 


66 GENERAL DESCRIPTION OF OTE-2 

Two units make up the main body of OTE 
Model 2, one of them electronic, the other me¬ 
chanical. Auxiliary equipment consists of a 
cabinet in which 24 program records and all 
necessary connecting cables can be stored. 
Functional connections between the OTE-2 and 
the standard sonar gear are shown in Figure 6. 

The electronic unit, a circuit diagram of 
which is shown in Figure 7, produces the essen¬ 
tial frequencies of the echo and reverberation 
signals and may be keyed either by the sonar 
stack or by a keying circuit in the mechanical 
unit. The latter method is used when the device 
is combined with a mockup stack rather than 
with an actual shipboard installation. 


The artificial reverberation, which has in¬ 
verse TVG, is controlled in frequency for own 
doppler by the mechanical unit and is modu¬ 
lated at random in both amplitude and phase. 
The signal, after it is generated in the elec¬ 
tronic unit, is controlled by the mechanical unit 
in its range, own doppler, target doppler, and 
bearing, and in accordance with the projector’s 
beam pattern. The control includes the phasing 
effect that is found in a split projector like 
that employed with BDI. 

When the OTE-2 equipment is used with 
BDI, the beam pattern is so controlled that 
audible echoes and center indications are ob¬ 
tained when the operator trains to the proper 
bearing; and the proper audible and visual sig¬ 
nals are received for any bearing that deviates 
slightly from the center bearing of the target. 
No echo is received, however, when the devia¬ 
tion between true target bearing and the bear- 



Figure 6. Block diagram—OTE-2 in relation to 
sonar gear. 


ing that the operator has determined is so 
large that an actual echo would not be received. 

The mechanical unit, shown in Figure 5, is in 
front of the instructor during the training pe¬ 
riod. The standard sonar bearing dial on the 
front panel has two indicators; one is the usual 
“bug” showing actual projector bearing; the 
other is a narrow pointer that indicates target 


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62 


TRAINERS FOR ANTISUBMARINE WARFARE SONAR OPERATORS 



RESTRICTED 


Figure 7. Wiring schematic for OTE-2. 















































































































































































































ELECTRONIC UNIT 


63 


bearing. The projector bug is coupled to the 
training wheel on the sound stack through a 
servo-synchro system, while the pointer is con¬ 
trolled by a target-bearing cam on the program 
record being used. Thus, whenever the operator 
is following the target bearing closely, the posi¬ 
tion of the bug will coincide with that of the 
pointer. Observation of these two indicators 
enables the instructor to keep a continuous 
check on the performance of the operator in 
determining target bearing. 

Below the bearing indicator are two small 
windows which permit the instructor to check 
the values of doppler and range as they are 
called by the student. 

During the attack the sliding drawer shown 
protruding from the lower part of the panel in 
Figure 5 carries a sheet of standard letter 
paper on which a pencil lead traces a continu¬ 
ous record of all the bearings determined by 
the student operator. The pencil lead is con¬ 
nected mechanically to the bug of the bearing- 
indicator and records the relative bearing of 
the projector by transverse motion. The drawer, 
which is closed at the beginning of the attack, 
is driven outward as the attack proceeds by a 
constant-speed motor controlled by the switch 
on the panel of the mechanical unit marked 
“program.” Drive is effected through a rack 
that can be disengaged at the end of the at¬ 
tack. As the drawer moves out, the active edges 
of the cams on the program record move against 
their respective followers and so transmit to 
the electronic unit the three types of attack 
information referred to above. The time re¬ 
quired for the drawer to open its full distance 
is four minutes, which is ample for most at¬ 
tacks. 

At the end of the run the paper is removed 
from the drawer, and a line showing the cor¬ 
rect sequence of bearings is superimposed on 
the student’s trace simply by placing the pro¬ 
gram record on the paper and drawing a pen¬ 
cil along the bearing cam. A typical record is 
shown in Figure 8. 

Echo timing, target doppler, and bearing in 
the mechanical unit are controlled by means of 
cam followers that move on the rectilinear cams 
on the program records, one of which is shown 
in Figure 5. A record is built up from three 


pieces of hard Masonite, each with one straight 
edge. In making the record, the pieces are 
stacked and glued together with the straight 
edges in line. The curved edge of the largest 
piece is cut as a rectilinear cam in accordance 
with the variation in relative target bearing 
during the attack which is being simulated. 
Similarly, the curved edges of the middle-sized 
and smallest pieces are cut to correspond to 
data pertaining, respectively, to target doppler 
and target range variation. A sketch of the en¬ 
tire attack is drawn on the back of the program 
record for the convenience of the instructor in 


See 



selecting the type of attack he wishes to repro¬ 
duce for the student operator. 

When in use, the program record fits against 
a set of guides in the left side of the movable 
drawer in the mechanical unit and it holds the 
recording paper in position. 

6-7 ELECTRONIC UNIT 

Reverberation and echoes encountered under 
actual service conditions possess certain char- 


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64 


TRAINERS FOR ANTISUBMARINE WARFARE SONAR OPERATORS 


acteristics that the OTE-2 must duplicate if it 
is to be satisfactory. These effects may be sum¬ 
marized as follows. 

1. Reverberation is loud immediately after 
the ping and diminishes with time. 

2. Reverberation is composed of a band of 
frequencies instead of a single frequency and 
shows irregular fluctuations in amplitude and 
phase at the two sides of the projector. 

3. Echo intensity is a function of target 
range, decreasing as range increases. 


Reverberation 

The reverberation signal is generated by an 
oscillator operating at approximately 20 kc, 
the frequency of the sonar gear. This oscillator 
is frequency-modulated at random over a small 
band by a noise generator and a reactance 
tube. In addition, the frequency of the rever¬ 
beration is adjusted by a d-c voltage applied 
to the reactance tube grid to include doppler 
from own-ship’s motion. The value of this d-c 



4. The echo, as received, is modified by a 
combination of two dopplers, one caused by 
own-ship’s motion and the other by the motion 
of the target. The result of this combination 
may be to give an echo frequency either higher 
or lower than that of the ping, depending on 
the tactical situation. 

The manner in which these effects are dupli¬ 
cated electronically in the OTE Model 2 is 
explained in the following paragraphs. In this 
connection the reader should refer frequently 
to the block diagram given in Figure 9, in 
which the type of signal emitted by each com¬ 
ponent is indicated. 


voltage is determined by the projector bearing 
and the ship’s speed as set into the device. 

The output of the oscillator is passed through 
an inverse time-varied gain stage that causes 
the signal level to decrease with time after the 
keying pulse is initiated. This decrease in level 
simulates the dying out of reverberation that 
follows the ping in ordinary sonar operation. 

The output of the inverse TVG stage is fed 
into a mechanical phase-and-amplitude modula¬ 
tor located in the mechanical unit. This modu¬ 
lator consists of a motor-driven rotary cam of 
irregular contour that activates two cam-fol¬ 
lower arms bearing on it on opposite edges. 


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ELECTRONIC UNIT 


65 


Each of these arms carries a small coil which, 
because of the irregular shape of the cam, is 
made to move back and forth across the face 
of two stationary coils that are connected in 
phase opposition. The output of one set of the 
stationary coils is phase-shifted through 90 
degrees and the output of the other set is con¬ 
nected between the electric center of the lag¬ 
line load and ground. The net result is an 
output that consists of two channels, with 
reference to ground, that are of random rela¬ 
tive phase and amplitude because of the motion 
of the moving coils. The signal finally obtained 
is intended to duplicate the characteristics of 
the reverberation obtained in actual echo rang¬ 
ing with a split projector. 

When the unit is used with equipment that 
does not include BDI and a split projector, the 
two channels are connected together. In this 
case the output from the center of the bridging 
network will be equivalent to the output of an 
unsplit projector. 

Time Delay and Echo-Triggering Pulse 

The keying pulse is fed into a circuit that 
gives it a time delay corresponding to the range 
of the echo as established by the range cam 
on the program record. This circuit operates as 
follows. 

A 6SJ7 tube is connected so as to operate as 
a constant-current pentode. The current from 
this tube charges a capacitor in series with a 
potentiometer that gives a voltage determined 
by the range cam on the program record. The 
time delay is a linear function of this voltage. 

The sum of the capacitor voltage and the 
variable potentiometer voltage is applied to the 
input of a two-stage d-c amplifier. The output 
of the d-c amplifier raises the grid voltage of 
a thyratron. When the thyratron fires, it de¬ 
livers a positive pulse across the load resistor 
between the cathode and ground. 

This positive pulse excites a typical multi- 
vibrator-type pulse generator which then de¬ 
livers another positive pulse, the length, shape, 
and amplitude of which are determined by 
fixed time constants in the multivibrator cir¬ 
cuit. This second positive pulse is then applied 
to the grid of the echo-keying tube, making it 


conducting and permitting passage of a pulse 
of the oscillator signal that serves as the echo. 

Generation 

The oscillator that initiates the echo signal 
has an associated reactance tube that is acti¬ 
vated by a d-c potential composed of two parts, 
one representing own-ship’s doppler as de¬ 
termined by the training of the projector, and 
the other representing target doppler as de¬ 
termined by the doppler cam on the program 
record. When the target doppler is equal to 
zero, the echo-oscillator frequency is equal to 
the mean frequency of the reverberation oscil¬ 
lator. 

The output of the echo oscillator is fed into 
an inverse time-varied gain switching stage, 
the grid bias of which is increased in a negative 
manner as a function of time so that its output 
level drops as a function of time after the 
keying pulse (ping) is sent out. This decrease 
in level is so adjusted that it simulates the 
normal decrease of echo level as a function of 
target range. 

This stage is kept inoperative by a large 
negative bias on the suppressor grid, and 
thereby prevents the echo signal from passing 
to the other circuits until such time as is speci¬ 
fied by the setting of the range cam on the 
program record. At this time the positive pulse 
from the multivibrator generator is applied to 
the suppressor grid, canceling the negative bias 
and permitting normal operation. The gain, 
and as a consequence the intensity, of the 
emitted echo, are determined by the amount of 
bias on the grid at the time the keying pulse 
occurs. The intensity of the simulated echo 
thus becomes a function of target range, just 
as it is in actual echo ranging. 

The output of this switching stage is de¬ 
livered to a cathode-follower stage that acts 
as an impedance-matching device to pass the 
signal to the projector simulator coils in the 
mechanical unit. These coils, when properly 
aligned by the operator, allow the signal to pass 
into the BDI and give right, left, or center 
indication, according to their relative place¬ 
ment. 

A complete circuit diagram of OTE Model 2 
is shown in Figure 7. 


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TRAINERS FOR ANTISUBMARINE WARFARE SONAR OPERATORS 


68 MECHANICAL UNIT 

The mechanical unit contains all of the prob¬ 
lem-generating elements, including the motor- 
driven program-record drawer previously de¬ 
scribed. The various components of this part 
of the equipment operate as follows. 

The Target Bearing, Doppler, and 
Range Cams 

The target-bearing cam operates mechani¬ 
cally through a gear section and follower gear, 
to revolve the exciter coil of a set of projector 
simulator coils so that at any moment the posi¬ 
tion of this coil gives the called-for bearing 
angle of the target. 

The target doppler cam varies the position 
of the arm on a potentiometer, which delivers 
a d-c voltage proportional to the called-for tar¬ 
get doppler. 

The target range cam, through a cam fol¬ 
lower, adjusts a potentiometer similar to the 
one mentioned above, which delivers the d-c 
range-determining voltage mentioned in the 
discussion of time delay and echo-triggering 
pulse generation. 

The Simulator Coils 

The amplitude and quadrature coils of the 
set of projector simulator coils a are carried by 
a disk that is driven by a servo-synchro system. 
This servo drives the amplitude and quadrature 
coils so that they assume a position correspond¬ 
ing to the bearing which the operator has 
set on the sonar stack training wheel. When 
the operator trains close to the bearing called 
for by the cam, the projector simulator coils 
approach coincidence and, as a consequence, 
echoes are heard, and right, left, or center in¬ 
dications are obtained on the BDI. These in¬ 
dications correspond to the relative positions 
of the cam-driven exciter coils and the quad¬ 
rature and amplitude coils manipulated by the 
operator. 

The servo system that drives the quadrature 
and amplitude coils also moves the recording 
pencil in a corresponding linear motion per¬ 
pendicular to the motion of the drawer. As 

a For a complete discussion of the operation of pro¬ 
jector simulator coils, see Chapter 11 of this volume. 


stated before, this pencil records the perform¬ 
ance of the operator in tracking the target. 

The bar that carries the pencil also moves 
a contact across a potentiometer strip. This 
potentiometer is so shaped that it delivers a 
voltage the amplitude of which is proportional 
to the cosine of the angle of deviation of the 
operator-controlled relative projector bearing. 
The absolute value of this voltage is controlled 
by a potentiometer located on the panel of the 
unit and graduated in ship’s speed. Thus, the 
voltage delivered is proportional to the doppler 
caused by own-ship’s motion. This potentiom¬ 
eter must be set by the instructor to the speed 
of the attacking ship, which is indicated on the 
back of the program record. 

Keying Control (Pinging) 

In order that the keying may be done at the 
proper range rate, the keying signals may be 
taken from either the sonar stack or from a 
range recorder. However, keying for the stand¬ 
ard range scales of 1,000 and 2,000 yd is avail¬ 
able in the mechanical unit itself in case it is 
inconvenient to use either of the above sources. 
The type of keying to be used is controlled by a 
three-position switch located on the panel of 
the unit. 

The keying built into the mechanical unit is 
accomplished by a cam driven by the same 
motor that operates the mechanical phase and 
amplitude modulator coils. The cam may be 
made to operate either or both of two contacts 
that are 180 degrees apart. Since the cam 
rotates once every 2*4 sec, the use of one con¬ 
tact gives keying equivalent to a 2,000-yd range, 
and the use of both contacts gives keying equiv¬ 
alent to a 1,000-yd range. 

69 GENERAL DESCRIPTION OF OTE-10 

During the later stages of the development 
of OTE Model 2, it seemed that the device 
might lend itself to training several operators 
simultaneously, by the use of one master unit 
such as the OTE Model 2, to furnish attack 
information to several student positions at the 
same time. The proposed extension of the de¬ 
vice was designated OTE Model 10. 

At the instructor’s station there was to be a 


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CONCLUSIONS 


67 


mechanical unit similar to that described for 
OTE Model 2, and the attack problem was to 
be generated by the same type of program 
record and other equipment as before. No 
record of operator performance would be made, 
however, at this station. If it were decided that 
ship’s course must be simulated so as to appear 
on the student-station gyro repeaters, a fourth 
cam could be added to each of the program 
records. The instructor’s station would also 
include an electronic unit similar to the one 
used in OTE Model 2. 

Each student station, located in a separate 
booth, would contain either a standard sonar 
equipment, with or without BDI, or a mockup 
stack. Mounted on top of each student’s sound 
stack would be an arrangement similar to the 
one in the drawer of the OTE-2 mechanical 
unit for recording the student’s performance 
in following the target bearing. Experience 
with the Model 2 unit has shown that it might 
be desirable to have this part of the equipment 
record the student’s bearing error for each 
point on the bearing trace rather than his 
actual obtained bearing, since such a procedure 
would permit a more open bearing scale. 

The placement of the simulator coils in the 
OTE-IO student recorder would differ some¬ 
what from the OTE-2 arrangement in order to 
permit plotting bearing error on the student’s 
record sheet. A servo-synchro system would 
provide a motion proportional to the target 
bearing called for by the problem. This system 
would be connected to one side of a mechanical 
differential, and the other side would be acti¬ 
vated by the student’s turning the bearing¬ 
training handle. The output of the differential 
would then be equal to the angular difference 
between the target bearing and the bearing 
obtained by the student. This mechanical mo¬ 
tion, which would be relatively easy to accom¬ 
plish, would change the position of only one 
exciter coil in the simulator coil assembly, while 
the other three projector coils would remain 
fixed. 

6.io CONCLUSIONS 

Only one unit of OTE Model 2 was con¬ 
structed. Laboratory tests indicated that its 


performance was functionally satisfactory but 
that the mechanical design was insufficiently 
rugged. The OTE Model 2 equipment provides 
a relatively simple method of simulating a 
number of the essential conditions that exist 
in an actual attack. With it, the student opera¬ 
tor using actual sonar gear can gain experi¬ 
ence and practice in attack procedure. While 
doing this, he makes a permanent record of 
his own performance that may be used for 
evaluation purposes and kept for future refer¬ 
ence. 

The OTE Model 10 design offers the possi¬ 
bility of giving a number of student operators 
simultaneously the kind of instruction and 
practice that OTE-2 provides for one student 
at a time. It has been estimated that runs could 
be made with this equipment at the rate of 
approximately six per hour, with ten to twelve 
student operators participating in each run. 
Thus, OTE Model 10 would accomplish a con¬ 
siderable economy of time in the use of skilled 
instructor personnel. 



Figure 10. BDI trainer (left) with advanced 
bearing teacher. 


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TRAINERS FOR ANTISUBMARINE WARFARE SONAR OPERATORS 


BDI Trainer 

The BDI trainer (Figure 10), developed by 
UCDWR, is a device for use in conjunction with 
the advanced bearing teacher or the Sangamo 
attack teacher to simulate BDI indications for 
training purposes. It ivas also intended to serve 
as a component of the group operator trainer 
[GOT]. It is similar in appearance to a BDI 
unit, with dummy balance and input selector 
controls. A range selector switch provides range 
settings at 1,000, 2,000, 3,000, and 5,000 yd. A 
gain attenuator controls the amplitude of re¬ 
verberation and target echo deflections on the 
BDI oscilloscope screen. Reverberation and 
echo signals, along with keying pulses, and true 
bearing information for both target and pro¬ 
jector are supplied by the associated attack 
teacher. 


611 INTRODUCTION 

Concurrently with the Harvard development 
of the OTE-8 as a BDI training aid for use 
with the QFD advanced bearing teacher, other 
engineers were working on a similar device, 
known as the BDI trainer, functioning on a 
different principle. While OTE-8 independently 
produces ultrasonic reverberation and echo sig¬ 
nals in synchronism with those of the QFD, 
the BDI trainer is designed to utilize the signals 
generated by the advanced bearing teacher or 
the Sangamo attack teacher itself. It was also 
intended that the BDI trainer should become 
a component part of GOT. Since the develop¬ 
ment of GOT was delayed because of priori¬ 
ties, and the BDI trainer was meanwhile com¬ 
pleted, the latter was delivered to the West 
Coast Sound School [WCSS] as a separate unit 
for service with existing training devices. 


612 CHASSIS DESCRIPTION 

The cabinet and controls of the BDI trainer 
are similar to those of the regular BDI (see 
Figures 10 and 11). As the attack teacher keys, 
the cathode-ray spot starts at the bottom of 
the screen and proceeds upward at a speed 


determined by the setting of the range selector 
switch (1,000, 2,000, 3,000 or 5,000 yd). The 
amplitude of the reverberation and echo de¬ 
flections is controlled by the gain attenuator on 
the right. (The balance and input selector con¬ 
trols are dummies on this model but may be 
made to perform as on the BDI.) The associated 
attack teacher supplies echo, reverberation, 
keying pulse, true target bearing, and true 
projector bearing information necessary for the 
operation of the BDI trainer. 


613 DESCRIPTION OF CIRCUITS 

Right-Left Echo Channels 

The echo signal after amplification is split 
into two channels for right and left echo de¬ 
flection. The bearing control section operates 
the bias of these tubes so that transmission of 
the echo through each channel occurs at two 
or three degrees off the center bearing of the 
target. The echo voltages are rectified, combined, 
filtered, and then applied to the cathode-ray 
oscilloscope [CRO] amplifier so that one chan¬ 
nel or the other supplies the echo pulse to the 
rectifiers as the projector bearing changes from 
right to left of the target bearing. A corre¬ 
sponding positive or negative pulse from the 
rectifier is supplied to the CRO amplifier to 
move the spot on the screen either to the right 
or the left corresponding to the target bearing 
deviation from the projector bearing, the range, 
and the amplitude of the received echo. 

Bearing Control 

To obtain the right-left indications, the 
voltages from the true projector bearing re¬ 
peater are connected to a control transformer 
whose rotor is positioned by the true target 
bearing. The coupling and adjustment is such 
that zero voltage is developed across the re¬ 
sistors of the control transformer when the 
projector and target bearings are the same. 
When these bearings differ, a 60-c voltage will 
appear, the magnitude depending upon the 
difference between the target bearing and the 
projector bearing. 

This voltage is impressed through isolating 


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DESCRIPTION OF CIRCUITS 


69 



Figure 11. BDI —front panel. 


resistors to the control grids of a twin triode 
V-110. The cathodes of V-110 are phase-dis¬ 
placed by a 60-c voltage. This results in a phase 
difference between the a-c voltage on the 
cathode and the a-c voltage on the grid at each 
half of the tube V-110. Therefore, as the pro¬ 
jector is trained through the target bearing, 
the a-c voltage applied to the grids of V-110 
undergoes a 180-degree phase reversal. One 
half of tube V-110 will draw its maximum cur¬ 
rent when the projector bearing is slightly to 
the right of the target bearing and the other 
half when the projector is trained slightly to 
the left of the target bearing. 

The outputs of V-110 are filtered, and the d-c 
component is used to control the echo channels 
for right-left deflection. The bias adjustment 
potentiometers P-9 and P-10 are used to control 
the width of the lobes, which, in this case, are 
set at approximately a total width of 40 de¬ 
grees. Therefore, the BDI trainer does not 
recognize width of targets but is dependent on 
the amplitude of the echo received from the 
attack teacher for cut-ons and cut-offs. 

Reverberation 

The reverberation is amplified in one half 
of the twin triode V-107 and is then applied to 
one half of the diode V-108 for rectification. 
The rectified reverberation pulses are applied 
to a 30-c band-pass filter. This band-pass filter 
blocks all but the 30-c component, which is then 
combined with the d-c pulses from the echo 
channel and applied to the CRO amplifier. 
Therefore, the visual reverberation is synchro¬ 
nized with the audible reverberation in length 
and decay time. 

CRO Amplifiers—Sweep and Intensity 
Modulation 

A pentode, V-101, is used as the sweep gen¬ 
erator and is similar to the one used in the 
BDI. A bridge is formed by a positive and 
negative power supply, the vertical deflection 
coil, and tube V-101. The speed of the sweep 
is determined by the capacity of the condenser 
C-l. The intensity modulation is obtained by 
combining a portion of the echo and reverbera¬ 
tion from the inputs, amplifying them in one 
half of triode tube V-109 and rectifying them 


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70 


TRAINERS FOR ANTISUBMARINE WARFARE SONAR OPERATORS 



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-250 VO-*-- 

Figure 12. Electrical schematic for BDI trainer, 














































































































































SUGGESTED IMPROVEMENTS 


71 


in the other half connected as a diode. The 
output is then filtered and applied to the con¬ 
trol grid of the CRO tube V-lll, so that the 
presence of any reverberation or echo gener¬ 
ates a positive voltage which decreases the bias 
and thus brightens the spot on the CRO tube 
V-lll. One half of the tube V-108 is connected 
from the control grid of tube V-lll to its 
cathode divider P-7 and R-40 to serve as an 
intensity limiter so that the brightening can 
never exceed certain limits. Two regulated 
voltage supplies are furnished to minimize 
drifting of the CRO spot. 


614 ADVANCED BEARING TEACHER 
CONNECTION 

Some modifications are necessary in connect¬ 
ing the BDI trainer to the advanced bearing 
teacher. 

1. The echo and reverberations must be 
brought out separately and supplied to the BDI 
trainer. 

2. A keying adapter must be used to actuate 
the keying relay in the BDI trainer since no 
current may be drawn from the voltage pulse 
already contained in the bearing teacher. 

3. A small i-f autosyn repeater must be 
geared to the target bearing in the mechanical 
portion and a 1-CT control transformer geared 
to the handwheel for projector bearing. The 
control transformer feeds into the BDI trainer. 
Either the i-f autosyn or the 1-CT control trans¬ 
former must then be rotated until a voltage 
null is obtained when the handwheel is trained 
to center bearing. 


615 SANGAMO ATTACK TEACHER 
QFA-2 CONNECTION 

Modifications are also necessary in connect¬ 
ing the BDI trainer to the Sangamo attack 
teacher (QFA-2). 

1. A separate light source must be added 
to the QFA-2 to generate true target bearing. 
This light source projects a series of parallel 
lines on to the screen surrounding the projected 
images of the vessels. These lines must be kept 


parallel with an imaginary line between the 
two vessels by manual operation. This is ac¬ 
complished by turning the knob on the light 
projector which rotates the lenses of the pro¬ 
jector. The lens rotating mechanism is geared 
to the rotor of the 1-CT control transformer. 

2. A keying adapter must also be used on the 
QFA-2 since only a voltage pulse is available 
on this model. 

3. In order to obtain echo and reverberation 
signals on the BDI trainer, separate lead con¬ 
nections must be made to the electronic chassis 
in the QFA-2. 

616 SUGGESTED IMPROVEMENTS 

1. A keying circuit operating from a voltage 
pulse should be incorporated, since most of the 
equipment with which it may be operated will 
have only voltage pulses available. 

2. A better light source is indicated for use 
with the Sangamo attack teachers since the 
BDI trainer can indicate training errors of 
1 degree or less. The light source now in use 
shoots parallel lines onto the screen, surround¬ 
ing the submarine and attacking vessel. These 
lines are neither close enough together nor 
anchored to either ship for easy alignment to 
within 1 degree of the true target bearing. 
Therefore, either additional lines are needed 
or a single beam anchored at one ship in the 
manner of the Sangamo BDI trainer. 

3. With the first attempt at connecting the 
BDI trainer to the QFA-2 attack teacher, a 
very poor signal-to-noise ratio was encountered. 
No attempt was made to correct this defect. 

4. As there is more than sufficient gain in 
the echo and reverberation channels in this 
model, the BDI trainer may be simplified by 
omission of one or two tubes. 

The group operator trainer was developed to 
overcome the disadvantage of individual in¬ 
struction to each student and to bring instruc¬ 
tion up to date through the use of more recent 
types of sonar stacks. Moreover, the trainer 
adds a number of new and more realistic sound 
effects and facilitates the teaching of various 
stack adjustments that were not possible on the 
advanced bearing teacher. 

The GOT equipment (see Figure 13) com- 


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TRAINERS FOR ANTISUBMARINE WARFARE SONAR OPERATORS 


prises ten soundproof booths containing stand¬ 
ard QGB or QJB stacks, and a master station 
for the instructor. The operator stacks include 
simulated transducers and have certain circuits 
revised to fit the application. The master sta¬ 


tion includes a sound effects chassis, a follower 
chassis, a keying chassis, a program generator, 
and ten indicators. These components and their 
operation will be described in the following 
section. 




INTERCOM 

VOLUME 

CONTROL 


TALK-USTEN 
SWITCHES- 


INTERCOM 

MICROPHONE-SPEAKER 

BEARING 
DIALS 


GRADING 


BEARING 


RECORDER 


INDICATORS 


START-STOP 


SWITCHES 


CONTROL 


KNOBS 


® ® (jr 




Figure 13. Standard QGB stack and master station console. 


Group Operator Trainer 


The group operator trainer [ GOT ], developed 
by UCDWR, is a device which simultaneously 
trains ten student ASW sonar operators (five 
on QGB and five on QJB equipment) under the 
direction of one instructor. It presents to the 
operators six different cam-controlled attack 
problems or continuous series of automatically 
generated ranges and bearings, together with 
realistic sound effects. Ten indicators on the 


master station show the instructor the correct 
center bearing of the submarine and the bear¬ 
ing to which each student is trained. Another 
indicator permits a permanent record of each 
student’s performance in training on the 
target. An intercommunications system alloivs 
the instructor to listen to each student’s reports 
at ivill and to give individual or group instruc¬ 
tion. 


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GENERAL DESCRIPTION 


73 


617 GENERAL DESCRIPTION 

The master station console, shown in Figure 
13, has three panels. On the left-hand panel 
are concentric bearing dials, on which a bug 
indicates the “right answer” center bearing of 
the submarine. On the center panel, ten dials 
indicate the respective bearings to which the 
students’ “projectors” are trained. Below these 
are control knobs, which regulate the various 
sound effects, the depth of the “submarine,” 
and other factors of the problem. On the right- 
hand panel are grading-recorder control but¬ 
tons for the two-way communication system 
between instructor and students, and three on- 
off switches. The latter are to switch the power, 
to start the problem, and to reset the problem, 
respectively. 

Once a problem is started, the simulated 
relative movements develop independently of 
the instructor and the students. The cam ar¬ 
rangement that controls the problem is so con¬ 
structed that own ship is conned perfectly for 
the attack. Six different attacks are included 
in the repertoire of the device. These are 
grouped in three pairs, each consisting of an 
attack and a reattack. The instructor can select 
any one of the pairs by an adjustment made 
through a side opening in the console. 

A student QGB station is shown in the left- 
hand side of Figure 13. Specific changes made 
in the QGB stacks include the substitution of a 
d-c selsyn transmitter for each bearing repeater 
selsyn. This is geared to the handwheel by a 
simple gear assembly. An electronically simu¬ 
lated projector is introduced into the stack to 
permit the echo to be heard on the proper 
bearings only. An electronic differential relay 
is also introduced to deliver information to 
the grading recorder. Circuits are arranged 
so that the bearing deviation indicator and the 
keying action of the indicator-recorder at each 
stack are controlled from the master station. 
A relatively simple wiring harness takes care 
of most of the wiring changes. 

In each QJB stack, the driver amplifier as¬ 
sembly is removed and a QJB adapter and 
simulated transducer assembly is substituted. 
The power input transformer is rewired for 
115 volts instead of for the customary 440 volts. 


The indicator-recorder and keying amplifier 
chassis wiring is revised to change the sequence 
of automatic keying and training to bring this 
sequence into conformity with the keying con¬ 
trols from the master station. 

The master station measures approximately 
32x45x60 in. and weighs 500 lb. 

The names and the functions of the center 
panel controls are as follows. 

1. The reverberation gain control varies 
simultaneously the intensity of reverberation, 
the water noise, and the surface wake effects. 

2. The reverberation range switch selects 
the duration of reverberation sounds after each 
ping. 

3. The water-noise gain varies the intensity 
of water noise. 

4. Water-FXR switch. When this switch is 
set at FXR, sound conditions are simulated 
that are present when FXR gear is towed by 
own ship. The intensity of this noise is con¬ 
trolled by the water-noise gain control. When 
the switch is set at water, conditions without 
FXR are simulated. 

5. The propeller gain control varies the in¬ 
tensity of own-ship’s propeller sounds. 

6. The surface wake width, surface wake 
gain, and surface wake range controls pertain 
to a simulated surface wake which has no re¬ 
lationship to the submarine. They control re¬ 
spectively the apparent width, echo intensity, 
and range of the surface wake. 

7. The flyback switch sets the flyback at the 
indicated number of yards beyond the echo 
range. 

8. The echo-ivake control varies simultane¬ 
ously the intensity of the submarine echo and 
submarine-wake echo. 

9. The depth control varies range at which 
contact is lost on approach and therefore the 
apparent depth of the submarine. 

10. The tuning control detunes all the stacks 
simultaneously to give the students experience 
in retuning their gear. 

11. Key button. A momentary pressing of 
this button starts the keying cycle of the 
master station. Holding the button in for a long 
dash stops the keying cycle. 


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618 TECHNICAL DESCRIPTION 

The technical description of the group opera¬ 
tor trainer will center around the diagrams 
in Figures 14 and 15. 

The sound-effects chassis generates water 
noise, FXR noise, reverberation tone, echo tone, 
and propeller modulation. These sounds are 
regulated by various center-panel controls, but 
whenever the time element must be controlled 



Figure 14. Simplified block diagram of group 
operator trainer. 


(as in ping duration and range-governed echo 
delay) the sound effects are triggered by pulses 
from the keying chassis. The output of the 
sound-effects chassis is fed through the fol¬ 
lower chassis into the simulated transducers. 

The keying chassis contains a closed func¬ 
tional loop of timing circuits in which each 
successive timing operation is initiated by the 
preceding circuit; once started, the keying cycle 
is self-sustaining. Some of the time intervals 
change with the progress of the problem, and 
the control elements that govern them are 
located in the program generator. Besides regu¬ 
lating the production of sound effects, the out¬ 
put of the keying chassis provides keying and 
flyback pulses to all the student stations. 

The mechanical-electrical program generator 
functions as the “brain” of the GOT and estab¬ 
lishes the values of the eight variables that 
enter the problems of the trainer. Three of 
them (sub wake range, sub aspect, sub range) 
affect time intervals in the problems and are 
fed into the keying chassis; one (doppler) is 
fed directly into the sound-effects chassis; one 
(own course) runs the compass cards on all 


the student stations and on the left-hand panel 
of the master station; and three bearing varia¬ 
bles (wake displacement, relative bearing of 
sub, target width) are fed into the simulated 
transducers. 

The simulated transducer located at each 
student station compares the bearing set up 
by the problem generator with the bearing to 
which the student has trained, and if the stu¬ 
dent is on the target, the simulated transducer 
allows the submarine and wake echoes from 
the sound-effects chassis to enter the student’s 
receiving circuits. The simulated transducer 
circuits allow the standard BDI on the stack 
to function normally. 

Either turning the student’s training hand- 
wheel or operating the automatic search per¬ 
forms five different functions: (1) the bug on 
the student’s bearing dials is rotated; (2) the 
simulated transducer is rotated; (3) one of the 
ten projector bearing indicators at the master 
station follows and indicates the new bearing; 
(4) the grading recorder at the master station 
records any significant difference between the 
new and old projector bearings relative to the 
target bearing; and (5) the intensity of pro¬ 
peller and FXR noises is varied to correspond 
to the turning of the transducer toward or 
away from own-ship’s screws. 

Sound-Effects Chassis 

The water and FXR noises are generated in 
the Type 2050 gas tubes V-l and V-15, respec¬ 
tively. Use is made of the fact that the random 
irregularities in gas tube conduction produce a 
sound very much like water noise (Figure 15). 

The output of the water-noise generator is 
used in three ways. (1) After passing through 
S-l (water-FXR switch) and being amplified by 
V-8A, the noise voltage is applied to P-8 (water- 
noise gain), amplified by V-8B, and fed into 
Var-1 for frequency conversion and for mixing 
with other sounds. (2) The output of V-8A is 
also applied to P-6A (propeller gain), is modu¬ 
lated in the modulator V-9 by the output of the 
multivibrator V-10, and leaves the chassis 
through T-5 as own-ship’s propeller noise. (3) 
The output of V-l is coupled directly to the 
grid of V-2 to excite the reverberation tanks 
in the plate circuit of the latter tube. 


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Figure 15. Electrical schematic of group operator 

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TECHNICAL DESCRIPTION 


75 


When S-l is set at the FXR position, func¬ 
tions (1) and (2) of the preceding paragraph 
are accomplished by using the FXR noise source 
(V-15) instead of the water-noise source (V-l). 
In addition, part of the output of V-8B (now 
FXR noise) is fed directly into T-5 to be com¬ 
bined with the propeller sounds coming from 
V-9. When, later in the circuit, the intensity 
of the propeller beats is made dependent upon 
the relative bearing of the student’s projector, 
part of the FXR noise will accordingly also be 
bearing-dependent. 

The reverberation tanks in the plate circuit 
of V-2 consist of L-l, C-l, C-2, and L-2, C-6, 
C-7, respectively. They are loosely coupled to 
each other by C-4. Both tanks are tuned to 4 kc 
and are excited by the amplified output of the 
water-noise generator V-l. The wide-band char¬ 
acter of the exciting source and the exchange 
of energy back and forth through C-4 combine 
to produce the wavering character of rever¬ 
berations in the sea. The output of the rever¬ 
beration tanks is used for three purposes: (1) 
ping reverberations are simulated by the por¬ 
tion of the output fed to the reverberation 
modulator, V-3; (2) tone for the surface wake 
echo is provided to the surface wake modula¬ 
tor, V-4; (3) tone for the submarine wake 
echo is provided to the submarine wake modu¬ 
lator, V-12. 

The submarine echo is generated by the 4-kc 
echo oscillator V-6. This tube is actually a 
double triode, one half of which functions as a 
tuned-plate oscillator, feeding its output 
through the other half, which functions as a 
cathode follower. A potentiometer, P-406, 
slightly changes the resonant frequency to 
simulate the doppler effect. The output of V-6 
is fed into the submarine modulator V-ll. 

The general functions of the four modulator 
stages, V-3, V-4, V-12, and V-ll, are very much 
alike. These tubes are remote-cutoff type 6SK7 
pentodes in which the variable gain character¬ 
istic is utilized. The gain is controlled by vary¬ 
ing voltage from the keying chassis. The input 
to each tube is from one of the sound genera¬ 
tors, and the output goes into a varistor fre¬ 
quency converter. 

The reverberation modulator V-3 receives 
its tone excitation from the high side of the 


second reverberation tank discussed above. 
Under normal conditions, when the control grid 
is at a d-c ground potential through L-2, P-2, 
and R-9, the tube is biased beyond cutoff and 
no reverberation tones is fed to later stages. 
Upon the closing of contact K-102B in the 
keying chassis, condenser C-8A is charged to a 
positive 150 volts, reducing the grid bias on V-3, 
and causing the tube to supply a reverberation 
tone to the varistor frequency converter Var-1. 
After momentarily closing, contact K-102B re¬ 
opens, and C-8A discharges through the series 
combination of P-2 (reverberation range) and 
R-9. The resultant increasing bias causes the 
output of V-3 to decrease until the plate current 
is again cut off. 

The surface wake modulator V-4 receives its 
tone excitation from the high side of the second 
reverberation tank through P-4 (surface wake 
gain). Normally, the cathode is held at a posi¬ 
tive d-c potential with respect to the control 
grid. The screen grid is at the potential of the 
left-hand plate of V-l 13 in the keying chassis, 
which is normally less than the V-4 cathode 
potential. The plate current is cut off, therefore, 
and there is no output from the modulator. 
V-4 gives an output only when the plate current 
of the left-hand half of V-113 is temporarily 
blocked, allowing the screen grid of V-4 to rise. 
In this modulator and in V-12 and V-ll, the 
positive pulse from the keying chassis is fed 
to the screen grid through a filter network. 
The magnitude of the V-4 output is dependent 
upon the instantaneous grid bias, which in turn 
is dependent upon the time interval between 
the closing of K-102D and the above-mentioned 
blocking action. Contact K-102D closes momen¬ 
tarily at the time of the ping and charges C-8B 
to a positive 150 volts, which provides V-4 with 
a minimum bias and hence a maximum gain 
immediately after the ping. Then C-8B begins 
to discharge through P-106 and R-159, the bias 
increases, and the gain of V-4 decreases to 
simulate increasing range. The output of the 
modulator is fed into the varistor frequency 
converter, Var-2. 

The submarine wake modulator V-12 receives 
its tone excitation from the high side of the 
second reverberation tank through C-12. The 
principles of operation for V-12 are very 


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76 


TRAINERS FOR ANTISUBMARINE WARFARE SONAR OPERATORS 


similar to those for V-4, as described above. 
V-12 is also keyed through its screen grid as 
V-4 is, except that the controlling tube in the 
keying chassis is V-108 instead of V-113. How¬ 
ever, V-12 differs from V-4 in that the sup¬ 
pressor grid of the former performs a special 
blocking function. Normally, the suppressor 
grid of V-12 is at approximate cathode poten¬ 
tial. At the instant of pinging, K-102C closes, 
and C-51 charges through R-44, so as to put 
the suppressor grid at a negative ground 
potential with respect to cathode. This potential 
blocks the plate current in V-12 until C-51 has 
partially discharged through R-44, P-19, and 
R-48. The time for this discharge to take place 
corresponds to the range within which the ASW 
vessel cannot receive echoes because of the 
depth of the submarine. Inasmuch as the lost 
contact range and the depth of the submarine 
have been assumed in the GOT to be propor¬ 
tional, the center panel control of the discharge- 
circuit element, P-19, has been labeled “depth 
control.” The output of the modulator is fed 
into the varistor frequency converter Var-4. 

The submarine modulator V-ll functions in 
exactly the same manner as V-12. The output 
of V-ll is fed into the varistor frequency con¬ 
verter, Var-3. Frequency conversion is accom¬ 
plished in the sound-effects chassis by the com¬ 
bination of the modified Colpitts oscillator V-5 
and each of the varistors, Var-1, Var-2, Var-3, 
and Var-4, coupled by appropriate trans¬ 
formers. 

Each varistor receives the oscillator fre¬ 
quency and one of the 4-kc sound effects. The 
interaction between them produces a number 
of output modulation frequencies, among which 
is the difference frequency of about 20 kc that 
is later selected by filter circuits to the exclu¬ 
sion of all others. 

The outputs of Var-1 and Var-2 are combined 
and fed through P-5 (reverberation gain con¬ 
trol) into the follower chassis. The outputs of 
Var-3 and Var-4 are fed through P-7 and P-9, 
respectively, into the follower chassis. P-7 and 
P-9 are ganged on one control labeled “echo- 
wake.” 

Follower Chassis 

The follower chassis (Figure 15) performs 


two functions: it selects from each of the four 
sound-effects channels a band of frequencies 
centered on 20 kc, and it then distributes the 
sound effects to the ten student stations. 

Four identical band-pass filters are used, each 
consisting of two series-resonant circuits. 
Cathode followers are used to allow the use 
of low impedance lines in the distribution sys¬ 
tem and to decouple the student stations from 
each other. 

Keying Chassis 

Detailed operation of the keying chassis is 
given in Figure 16. The left-hand and middle 
columns of Figure 16 cover the internal work¬ 
ings of the chassis, and the right-hand column 
describes the outgoing pulses that are fed to 
other sections of the GOT. The five trigger cir¬ 
cuits (V-102, V-103, V-107, V-108, and V-113) 
used in the keying chassis are quite conven¬ 
tional. 

Program Generator 

The program generator (Figures 15 and 17) 
is built around 24 cams that contain in their 
contours all the problem elements of the GOT. 
The cams are mounted on a shaft in eight 
groups of three each. On a second shaft parallel 
to the first one are pivoted eight cam followers, 
spaced so that there is one follower for each 
group of three cams. The followers ride corre¬ 
sponding cams in the eight groups; and the 
remaining 16 cams, which contain the details 
of the other two pairs of problems, are idle 
until selected for a new problem. 

The camshaft is rotated through a drive- 
gear assembly which is driven by the problem 
motor, which advances the problem at a normal 
rate, or the reset motor, which reverses the 
problem at a rapid rate. 

A switching cam, in addition to the 24 prob¬ 
lem cams, forms a part of the drive-gear as¬ 
sembly. The cam operates two microswitches, 
which are displaced from each other by 90 
degrees: (1) S-402, which alternately turns on 
the blue and green lights on the left-hand panel 
at the beginnings of the two problems; (2) 
S-401, which, in the middle of each problem, 
simultaneously reverses polarity on the rela¬ 
tive-bearing selsyns G-402, G-403, and on the 


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TECHNICAL DESCRIPTION 


77 


Re | iet it ion of cycle 
Positive pulse 
comes from V-107 

I-. 

Voltage rise trisers V-103 

4 

Fixed time delay in 
R-109, C-106 
V-103 triggers back; 
negative voltage to V-111A 
Relay K-101 drops - 

I L 



TO START, press KEY switch S—3 
momentarily to apply positive 
pulse to V-103 


■ Positive voltage to V-111A 
■Viergizos relay K-101- 


k«± 


contacts K-101C discharge 0-101 
contacts K-101!) extinguish V-101 


-N.0. contacts K-101D 
send rectangular pulBe 
to gra'ling recorder to 
mark echo -> L 


Contacts K-101D are restored to normal 


Contacts K—101C open; let C—101 charge through P—16 (Flyback delay) 

V-101 fires; 

Voltage rise triggers V-102 -►Positive voltage to V-111B 

iinorgizes relay K-103-*- 

Fixed time delay in u’M.O. contacts K-1030 discharge C-110 

R-106, C-105 ¥¥.C. contacts K-1Q3U extinguish V-104 

V-102 triggers back; 
negative voltage to V-lllfl 

Relay K-103 ilrops -——__ r 


-*■ M.O, contacts K-103C 
oleie ground, and M.C, 
contacts K-103B send 
rectangular pulse to 
all flybacks 


¥ 


| * -►Contacts K-103S are restored to normal 

Contacts K—1030 open; let C—110 charge through R-121 (Fixed time delay) 
V-104 fires; voltage rise makes V-110 fire 
V-110 energizes relays K-104 and K-102 

-IT- I TIT 


• Keying pulse to 
all stacks 


1 


r N.O. contacts K-102E discharge C-1U 


N.C. 11 

It II 

K-102F extinguish V-106 

N.0. " 

It II 

K-102G discharge C-18 

N.C. " 

II It 

K-102H extinguish V-109 

N.C. " 

II It 

K-102J discharge C-125 

[N.C. " 

It It 

K-102K extinguish V-114 


N.C. contacts K-104B extinguish 7-110 


- Relay K-104 drops out 


Relay K-102 drops out 


•N.0. contacts K-102B n 
charge C8A to activate |\ % 
reverberation modu- -I ' 
lator V-3 

-N.0. contacts K-102C -> 
discharge C-129; sub- / 
depth to G-3 of V-ll L/ 
and 7-12 


M. C. contacts K-102F, H and K restored to normal 

N. 0, contacts K-102 G open 

Let C-18 charge through P-402 and V-105B 
(-Time delay for sub-wake echo) 

7-109 fires; voltage rise triggers 7-108 


• N.0. contacts K-102D 
discharge C-8B; echo 

attenuation through 
R-38 to of 7-11 
and through P-4 to 
Gj. of 7-4 and 7-12 


Time delay C-115 controlled by P-404B (trace length) 
7-108 triggers back -*- 


Sub-wake echo pulse 


to 


of 7-12 


Tv 


¥ 


II.0. contacts K-102J open 

Let C-125 charge through P-17 

(-Time delay for surface-wake echo) 
7-114 fires; voltage rises triggers 7-113 


Time delay C-122 controlled by P-18 (trace length) 
7-113 triggers back - 


Surface-wake echo ' 
pulse to of V-4 -* *- 


N.0. contacts K-102E open; 

Let C-1U charge through P-401 and V-105A 
(■‘Time delay for sub-echo) 



-Sub-echo pulse to 
02 of V-ll 


¥ 


Figure 16. Keying sequence. 


wake displacement Variac T-402, thus causing 
a 180-degree shift in bearing and a reversal of 
wake position to correspond to the passing of 
the ASW vessel over the submarine. 

Figure 18 is a simplified sketch of a cam and 


its follower mechanism. The control element 
may be a variable resistor, a selsyn, or a Variac. 

The first cam follower turns selsyn G-401, 
which in turn drives the master station com¬ 
pass-card selsyn (B-611) and the compass-card 


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78 


TRAINERS FOR ANTISUBMARINE WARFARE SONAR OPERATORS 



DIFFERENTIAL 
GEAR BOX 


TARGET WIDTH 
VAR I AC (T-401) 


TEE LEVER FOR 
SHIFTING PROBLEMS 


SUBMARINE-WAKE RANGE 
RESISTOR (P-402) 


SUBMARINE RANGE 
RESISTOR (P-401) 

(S-401, S-402) 
MICROSWITCHES 

DRIVE GEAR 


CRANK FOR LIFTING FOLLOWERS CLEAR OF CAMS 


PROBLEM 
MOTOR lB-401) 


RESET MOTOR 
(B-402) 


RELATIVE BEARING 
SELSYN COUPLED TO 
MASTER STATION 
BUG-RING SELSYN 


(G'403) RELATIVE BEARING SELSYN 
COUPLED TO BEARING CONTROL TRANS¬ 
FORMERS AT STUDENT STATIONS 
DISPLACEMENT VARIAC (T-402) 

COURSE SELSYN (G-401) 

AND WAKE ECHO-LENGTH RESISTORS (P-404A, P-404B) 


Figure 17. Program generator, front view. 


selsyns of all the student stations. G-401 is 
termed the own-course selsyn. 

The second cam follower turns the variable 
resistor P-402 that controls the time delay cor¬ 
responding to the submarine wake range. 

The third cam follower turns the two variable 
resistors P-404A and P-404B that respectively 
control the pulse lengths corresponding to the 
duration of the submarine echoes and wake 
echoes. In an actual attack, these durations 
depend upon the aspect of the submarine. 

The fourth cam follower turns the wake dis¬ 
placement Variac T-402. Inasmuch as the fixed 
connection on the Variac is a center tap, the 
variable tap can supply the simulated trans¬ 
ducers with voltages of both polarities to cor¬ 


respond to right or left displacements of the 
wake echo from the submarine echo. 

The fifth cam follower turns the variable 
potentiometer P-406, which varies the echo 
oscillator frequency in simulation of doppler. 

The sixth cam follower turns the variable 
resistor P-401, which controls the time delay 
corresponding to the submarine range. 

The seventh cam follower turns two relative¬ 
bearing selsyns: G-402 is coupled electrically to 
the bug-ring selsyn on the master-station bear¬ 
ing dials, to indicate the center bearing of the 
submarine; G-403 is coupled electrically to the 
bearing control transformers of the student sta¬ 
tions. In order to develop a minimum bearing 
voltage in the rotor of his control transformer 


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TECHNICAL DESCRIPTION 


79 


(on-target condition), each student must orient 
his rotor (his “projector”) to correspond to the 
position of the G-403 rotor. The bearing voltage 
is fed into the grading-recorder circuit to in¬ 
dicate whether the student is on target, and into 
the simulated transducer to control echo inten¬ 
sities and BDI indications. 

The eighth cam follower turns the target 
width Variac T-401. This Variac controls the 
amplitude of the 60-c voltage applied to the 
wake displacement Variac T-402 and to the 
rotor of the relative bearing selsyn G-403. 
Hence, as voltage output in the Variac in¬ 
creases, there is a simultaneous increase in the 
apparent angular displacement of the wake 
from the submarine, and in the apparent width 
of the target. 



Figure 18. Cam and follower mechanism. 


Simulated Transducer 

The simulated transducer (Figure 15) at 
each student station receives four input volt¬ 
ages: (1) the submarine-echo voltage from the 
follower chassis, (2) the submarine wake-echo 
voltage from the follower chassis, (3) the bear¬ 
ing voltage from the student station bearing 
control transformer, (4) the wake-displace¬ 
ment voltage from the problem generator. The 
two echo voltages enter the simulated trans¬ 
ducer with all the attributes appropriate to the 
problem in hand except those controlled by the 


bearing of the target. It is the function of the 
simulated transducer to modify the echoes in 
accordance with the bearing voltage and the 
wake displacement voltage. 

The simulated transducer consists of two 
circuits, which are identical except for input 
connections. On the diagrams, these circuits 
are arranged one above the other; the top cir¬ 
cuit modifies the submarine echo, and the bot¬ 
tom circuit modifies the submarine wake echo. 
Each of the two circuits has two identical chan¬ 
nels. Each channel consists of a phase-sensitive 
amplifier, a low-pass filter, a variable gain 
amplifier, and a phase-shifting network. The 
phase-sensitive amplifier produces an output 
voltage the magnitude of which depends on the 
phase and magnitude of the bearing voltage in 
the top circuit and on the phase and magnitude 
of the bearing voltage plus the wake-displace¬ 
ment voltage in the bottom circuit. The output 
of the phase-sensitive amplifier is fed through 
the filter to eliminate the a-c component, and 
the remaining d-c voltage is applied as bias to 
the grid of the variable-gain amplifier. Also 
applied to this grid is the submarine echo or 
the submarine walce echo. Variable gain is at¬ 
tained by operating the amplifier near the cut¬ 
off bias and by chopping off more and more 
of the signal wave as the bias is increased. Dis¬ 
tortion is eliminated, in the present application, 
by resonant circuits in the student’s receiver- 
amplifier. The output of the variable-gain 
amplifier is applied to a phase-shifting network 
that gives the echo the same phase character¬ 
istics as it would have in coming from the 
right or left half of a split transducer. 

The bearing voltage is applied to the simu¬ 
lated transducer through S-201 and R-244. The 
phase-sensitive amplifiers of the submarine echo 
channels are excited directly by this voltage 
through R-202 and R-203. The wake-displace¬ 
ment voltage is applied to the simulated trans¬ 
ducer through S-201 and T-201. By a series con¬ 
nection, this voltage is added to the bearing 
voltage; and the sum excites the phase-sensi¬ 
tive amplifiers of the submarine wake-echo 
channels through R-212 and R-213. 

A 60-c reference voltage is applied to the 
four cathodes of the phase-sensitive amplifiers 
from T-202. The connections are so made that 


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80 


TRAINERS FOR ANTISUBMARINE WARFARE SONAR OPERATORS 


the cathode potentials in each pair of ampli¬ 
fiers are 180 degrees out of phase. Thus, in the 
submarine echo circuit, when the student, by 
training slightly off target, excites the amplifier 
grids with the 60-c bearing voltage, the effect 
of the reference voltage is to increase the plate 
current in one triode and to reduce it in the 
other, an effect which in turn increases the 
output of the variable-gain amplifier in one 
channel and reduces it in the other. By training 
off the target in the opposite direction, the 
high-gain and low-gain channels are reversed. 

The plates of the variable-gain amplifiers in 
the submarine echo circuit are connected to the 
opposite ends of the phase-shifting network, 
consisting of C-216, R-241, R-242, and C-215, 
which feeds its output into the primaries of 
T-205 and T-203. In the secondary circuit of 
one of the latter transformers, the echo tone 
from one channel is advanced in phase by ap¬ 
proximately 45 degrees; in the other secondary, 
the echo tone from the same channel is re¬ 
tarded in phase by a similar angle. The echo 
tone from the second channel is also advanced 
and retarded respectively, by approximately 45 
degrees; only now the leading and lagging sec¬ 
ondaries have been reversed. In other words, 
the phase angles of the two channel voltages are 
of opposite sign in each secondary, and as the 
magnitudes of the two channel voltages ap¬ 
proach each other in value, the phase angle of 
the resultant voltage approaches zero. The 
BDI circuits of the student’s stack, to which 
the secondaries of T-205 and T-203 connect, 
are designed to interpret a deviation of the 
resultant voltage angle from zero as an off- 
target indication. Such an off-target indication 
will result whenever the bearing voltage from 
the bearing-control transformer is other than 
zero. 

The submarine wake-echo circuit of the simu¬ 
lated transducer functions in exactly the same 
manner as the submarine echo circuit. The two 
differ only in their input voltages. As previously 
mentioned, the input to the submarine wake- 
echo circuit consists of the sum of the bearing 
voltage and the wake-displacement voltage, in¬ 
stead of the bearing voltage alone. Hence, in 
order that the transducer may give an on-wake 
indication, the student must train the bearing- 


control transformer off the target until the 
bearing voltage is equal and opposite to the 
wake-displacement voltage, thus producing the 
necessary zero sum voltage. 

A type 6AF6 double indicator tube (V-207 
and V-206) is used in each transducer circuit 
to show balance. After adjustment is complete, 
the indicator tubes are pulled out of the sockets, 
and the circuits are operated without them. 

The discussion of simulated transducer op¬ 
eration has thus far involved only on-target or 
slightly off-target situations. As the student 
trains more and more off the target, the out¬ 
puts of both channels in each circuit are re¬ 
duced until they are cut off. 

Water noise, surface wake echoes, reverbera¬ 
tions, and own-ship’s propeller beats are mixed 
with the submarine and submarine-wake echoes 
in the output circuit of the simulated trans¬ 
ducer. These are all nondirectional sounds, ex¬ 
cept the own-ship’s propeller beats, which are 
given a directional characteristic by a student- 
station unit. The potentiometer P-107 is coupled 
mechanically to the stack training mechanism, 
to pass a maximum signal when the relative 
bearing of the imaginary projector is slightly 
less or slightly greater than 180 degrees. 

Indicators 

The instructor has before him four types of 
indicators to show the progress of the problem 
and the students’ reactions: (1) pilot lights, 
(2) bearing dials, (3) bearing indicators, and 
(4) a grading recorder. 

There are three pilot lights—red, blue, and 
green. The red pilot light (1-601) is actuated 
by the start button of the power switch. The 
blue or green light (1-603 or 1-602) indicates 
whether the first or second of the pair of cam 
problems (“attack” or “reattack”) is in prog¬ 
ress. 

Each conventional bearing dial consists of a 
compass card in the center, a bug ring, and a 
stationary relative-bearing scale on the outside. 
The bug indicates the true and relative center 
bearings of the submarine from the ASW 
vessel. Each of the ten bearing indicators 
(B-601 to B-610) has a bearing scale and a 
pointer, which show the relative bearing of 
the student’s projector. 


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TECHNICAL DESCRIPTION 


81 


The grading recorder is adapted from a 
Sangamo tactical range recorder by the sub¬ 
stitution of a new stylus assembly and a new 
gear and motor assembly. Figure 19 is a photo¬ 
graph of the recorder, and Figure 20 is a 
sketch showing the type of record produced by 
the device. Each of the ten student stations is 
represented on the recorder by three fixed styli. 
The center stylus marks the paper at the mo¬ 
ment during each target echo when contact 
K-101B on the keying chassis closes. This echo 
record is independent of the students’ actions. 
The right and left styli mark the paper when 
the student trains right and left respectively, 
from the center bearing of the target. The 
marking voltages for these styli are received 
from a student-station follower unit, which is 
excited by the bearing control transformer 
voltage. 



6 . 18.1 ]yj eans 0 f Coupling Stack Training 
Mechanisms to the GOT 

In the previous sections covering the techni¬ 
cal description of the GOT, references were 
made to the coupling of four GOT elements to 
the training mechanism of each student stack. 


These elements are (1) the bearing control 
transformer, (2) the bug on the student’s 
bearing dials, (3) the indicator-transmitter 
potentiometer, and (4) the propeller-beat po¬ 
tentiometer. 

In the QGB, the bearing control transformer 
is the synchro that is already connected me¬ 
chanically to the training handwheel; thus the 
only modification necessary is to change its 
wiring. A simple gear train is installed to 



Figure 20. Typical record made by the grading- 
recorder. 


couple the shaft of the control transformer to 
the other three elements. The student, there¬ 
fore, drives all four units by the torque that he 
applies to the handwheel. 

In the QJB, an adapter unit is installed on 
the same chassis as mounts the simulated trans¬ 
ducer and the grading-recorder follower unit. 
The drive selsyn of the adapter unit is coupled 
electrically to the training mechanism of the 
QJB and drives the bearing control trans¬ 
former, the indicator-transmitter potentiom¬ 
eter, and the propeller-beat potentiometer 
through a train of gears. Indirectly, the drive 
selsyn also moves the bug on the student’s 
bearing dials by driving a 1-G selsyn. The 1-G 
selsyn is coupled electrically to a control trans¬ 
former, which is part of the servo system that 
positions the bug. 


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Chapter 7 

RECORDER OPERATOR TRAINERS 


T hree devices were developed to assist in 
training range recorder operators: the ele¬ 
mentary range recorder teacher, the QFL 
tactical range recorder teacher, and the re¬ 
corder trace projector. All three are covered in 
this chapter. 



Figure 1. Elementary range recorder teacher. 


Following the development of the chemical 
sound-range recorder, the need for some simple 
means of giving elementary instruction in the 
operation of this device became apparent. As 
a stopgap measure, the elementary range re¬ 
corder teacher was designed, and 25 units were 
constructed and delivered to the West Coast 
Sound School [WCSS]. 

Figure 1 shows the mockup of the chemical 
sound range recorder face which constitutes 
the elementary range recorder teacher. A 
printed trace recorded at sea is inserted in the 
device, and the dummy controls shown in the 
figure give the student practice in manipulating 
the plotter bar, setting the adjusters of the 


bow or stern scale and the ship’s speed scale, 
determining ranges and range rate, and calling 
firing time. 

Although students can get a general idea of 
the elementary operations of the chemical 
sound range recorder from working with this 
teacher, its chief drawback is that it does not 
drill the trainee in routines exactly duplicating 
those which a sound range recorder operator 
should perform automatically. Since the dummy 
controls in the mockup are differently placed 
from those in a standard chemical sound range 
recorder, the student who has practiced on the 
teacher must re-learn the routine of operating 
these controls when he transfers from the 
teacher to an actual recorder. 

Elementary Range Recorder Teacher 

The elementary range recorder teacher pro¬ 
vides elementary training in the use of the 
chemical sound range recorder. Essentially it is 
a mockup of a chemical sound range recorder 
face which has been considerably simplified. It 
includes range and speed scales, a plotter bar, 
and a set of printed “sea” recordings, furnished 
with each unit. The bow or stern scale and the 
ship’s speed scale are placed above and slightly 
to the left of the range scale, plotter bar, and 
plotter bar extension, instead of in the lower 
right-hand corner, as in the operational sound 
range recorder. The adjusters for these scales, 
together with the plotter bar control, are the 
only controls embodied in the mockup. The 
printed copies of different types of traces re¬ 
corded at sea may be inserted in the “window” 
so that the student may practice interpreting 
traces, manipulating the plotter bar and its 
extension in line with the traces, and determin¬ 
ing range rate and firing time. This training 
device was developed by UCDWR. 

71 INTRODUCTION 

Prior to the development of the QFL tactical 
range recorder teacher, trainers for echo-rang- 


82 


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TECHNICAL DESIGN 


83 


ing equipment had used only electronically 
produced sounds. Such simulated sounds, par¬ 
ticularly reverberation, had never been truly 
realistic. Since sonar operators using later mod¬ 
els of sonar gear do not hear the outgoing ping, 
they must recognize doppler effects by compar¬ 
ing the frequencies of the submarine echo and 
of the reverberation and of the wake echo. 

The search for greater realism of reproduced 
signals, echoes, and reverberation in land-based 
trainers led to the development of the QFL 
tactical range recorder teacher, using phono¬ 
graph recordings of echo-ranging sounds made 
under operating conditions at sea. The record¬ 
ings provide signals which produce traces in 
five or more range recorders at the same time; 
accompanying sounds of echoes and reverbera¬ 
tions are heard through a loudspeaker. A stu¬ 
dent stationed at each recorder manipulates 
the recorder controls and interprets the traces 


exactly as he would in an actual attack on a 
submarine. 

The complete equipment is shown in Figure 
2. In the center is an amplifier control unit in 
which are mounted the record playback and the 
chassis carrying the various circuits for keying, 
trace control, and speech amplifying. The 
amplifier drives five sound range recorders and 
also feeds the signals into the loudspeaker. The 
power source for the amplifier is a 110-volt, 60-c 
outlet. Figure 3 is a complete wiring schematic. 

Shelves are provided in the lower part of 
the amplifier control unit cabinet for the rec¬ 
ords used with the equipment. There are 34 of 
these. One is a sensitivity adjustment record, 
used to test the equipment before putting it into 
regular operation. The remaining 33 are re¬ 
cordings of sound signals made during practice 
attack runs at sea. An instruction manual com¬ 
pletes the QFL equipment. 


QFL Tactical Range Recorder Teacher 



Figure 2. QFL tactical range recorder teacher. 


72 TECHNICAL DESIGN 

Three different models of the QFL tactical 
range recorder teacher were designed before 
the problems posed were satisfactorily met. 
The modifications made were chiefly in the 
amplifier control unit. 

Amplifier Control Unit 

Model 1 . The first experimental QFL model 
drove only one sound range recorder. Signals 
from a phonograph recording on the turntable 
were fed via a magnetic pickup, through an 
input transformer and a two-stage amplifier 
to an output transformer. The output of this 
transformer went to a power amplifier, which 


The QFL tactical range recorder teacher, de¬ 
veloped by CUDWR-NLL, consists of a series of 
five or more sound range recorders operating on 
signals from phonograph recordings; an ampli¬ 
fier control unit in which are mounted the 
record playback and the chassis carrying the 
various circuits for keying, trace control, and 
speech amplifying; and a loudspeaker. 

supplied the loudspeaker and the trace circuit 
of the recorder. In the keying circuit, the sig¬ 
nal voltage was rectified and brought to a 
thyratron with associated relays. The initial 
burst of reverberation energized one relay 
through the thyratron, engaging the clutch in 
the recorder and causing the stylus to be drawn 
across the paper. When the stylus reached the 
flyback contacts on the recorder, a second relay 
was energized, opening the plate circuit of the 
thyratron and thus causing the recorder clutch 
to disengage. 

This keying arrangement proved unsatisfac¬ 
tory. Often the initial burst of reverberation 
was too weak to operate the thyratron. Some¬ 
times extraneous noise impulses caused keying 
at the wrong time. Therefore, only one experi¬ 
mental model of this type was constructed. 


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84 


RECORDER OPERATOR TRAINERS 



Js 


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POWER SUPPLY FOR ALL TUBES 

Figure 3. Wiring schematic for QFL. 















































































































































































































TECHNICAL DESIGN 


85 


Model 2. This model employed a 75-c keying 
tone, instead of the initial burst of reverbera¬ 
tion, to key the recorders. The 75-c tone was 
adopted because it could readily be filtered out 
of the sound and trace circuits without causing 
any noticeable differences in either the sounds 
or the traces. Also, the amplitude of a tone of 
this frequency remains relatively constant on 
a recording, in spite of repeated playing. 

Signals from the magnetic pickup in this 
model go through an amplifier to a dividing 


recorders to provide direct keying from the 
full-wave rectified keying tone. Separate level 
adjustments were added for the three major 
channels. Minor circuit changes made it pos¬ 
sible to add more recorders in multiple, if de¬ 
sired. 

An oscillator and switching channel was also 
added to permit the printing of a variable 
length trace as the stylus begins to move across 
the paper. This feature simulates the printed 
signal trace which is used on some models of 



Figure 4. Block diagram of QFL Model 3. 


network having a crossover frequency of 200 c. 
Components above 200 c are fed through a 
power amplifier to the loudspeaker and recorder 
trace circuits. Components below 200 c, includ¬ 
ing the 75-c keying tone, go through a two- 
stage amplifier to a full-wave rectifier. The 
output of this rectifier energizes the thyratron 
and relays, as in Model 1. 

This keying arrangement proved depend¬ 
able. Five units of Model 2 were made and put 
into service at antisubmarine warfare [ASW] 
training centers. 

Model 3. The most important change initi¬ 
ated in Model 3 (see block diagram, Figure 4) 
was the elimination of the keying relays. Ad¬ 
vantage was taken of the thyratron in the 


the sound range recorder. Model 3 served as a 
manufacturer’s prototype for the production 
design of the amplifier control units. 

Sound Range Recorders 

The sound-range recorders attached to the 
QFL equipment are the same, with slight modi¬ 
fications, as those in operational use. The first 
five equipments (Model 2) were designed to 
operate with Model CAN-55100 Sangamo sound 
range recorder. Because later recorder models, 
when used with Model 3 QFL equipment, pro¬ 
vided less contrast between different parts of 
the trace than had been obtained with the 
CAN-55100 recorder, the traces were more diffi¬ 
cult to interpret. A special recorder was there- 


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86 


RECORDER OPERATOR TRAINERS 


fore developed for use with the QFL equipment. 

To adapt the recorder for use with the QFL 
teacher, the wiring was changed slightly so 
that the keying of the stylus is controlled by an 
external 75-c pulse, whereas in recorders used 
aboard ship the keying is automatic and sup¬ 
plied from circuits within the recorder itself. 
An extra stylus is mounted in a stationary posi¬ 
tion at the extreme left of the bars which carry 
the moving stylus. This extra stylus produces 
a dotted line along the left edge of the paper 
to mark the beginning of the simulated out¬ 
going signal. 

Phonograph Recordings 

Several hundred recordings were made of 
the sound signals received by echo-ranging 
surface craft through their echo-ranging equip¬ 
ment during practice attacks on target subma¬ 
rines under a wide variety of attack conditions. 
This material was edited to produce the QFL 
training series of 34 recordings which are ar¬ 
ranged in order of increasing difficulty. 

The series is designed so that, if necessary, 
it can be used without a trained instructor. It 
includes a sensitivity adjustment record for 
adjusting the equipment before beginning the 
training session. The remaining 33 records in 
the series contain the sounds received by ASW 
sonar equipment and the injected 75-c pulses for 
keying the recorders; they also give verbal 
descriptions and instructions. The drills pro¬ 
vided by the recordings include training in 
recognition of different types of target inclina¬ 
tion by the nature of the echo (beam, quarter, 
and bow targets), discrimination between tar¬ 
get and wake echoes, doppler recognition, 
knuckle wake recognition, in addition to prac¬ 
tice in setting the firing time analyzer and 
determining range rate and firing time. A full 
description of the QFL equipment may be 
found by consulting the bibliography. 1 

™ CONCLUSION 

Reports on the 63 QFL equipments which 
were constructed and distributed emphasized 
repeatedly their service as a training device. 
Their value lies especially in the fact that they 
closely simulate actual operating conditions and 


provide drills in order of increasing difficulty. 
A slightly modified version of the QFL equip¬ 
ment was developed for use in submarine train¬ 
ing activities to teach the operation of the 
sound range recorder as part of torpedo detec¬ 
tion gear. 


PLOTTER 

RANGE RATE BAR 

SCALE RANGE SCALES EXTENSION 



Figure 5. Screen of recorder trace projector. 


Recorder Trace Projector 

The recorder trace projector, developed by 
CUDWR-NLL for classroom demonstration of 
typical problems and conditions encountered in 
the operation of the sound range recorder, con¬ 
sists of a screen, projector, and a sound range 
recorder arranged so that the moving recorder 
traces may be projected onto the screen. The 
source for producing the recorder traces is a 
phonograph record in a QFL tactical range re¬ 
corder teacher or in a QFA (Sangamo) attack 
teacher. The screen is a reproduction of the 
analyzer and control mechanism of the sound 
range recorder enlarged to five times its original 
size and mounted vertically on a board. 

74 INTRODUCTION 

The recorder trace projector was developed 
originally to meet a need expressed by the Sub¬ 
marine Chaser Training Center in Miami, 
Florida, for a means of demonstrating the 
operation of the sound-range recorder in the 
classroom. 


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CONCLUSION 


87 


75 DESCRIPTION 

Screen 

The screen is a reproduction, with a few 
modifications, of the cover plate, range scales, 
and recording paper of a recorder. The black¬ 
board and the framework on which the moving 
parts of the screen are mounted are of wood; 
the plotter-bar extension is of sheet metal, with 
painted lines to simulate those on the trans¬ 
parent plotter-bar extension of an actual re¬ 
corder. Figure 5 shows the screen with the 
plotter bar in the zero range rate position. For 
the convenience of the instructor, a handwheel 
on an extension reaching to one lower corner of 
the blackboard is substituted for the hand knob 
used to control the plotter bar of an actual 
recorder. This is the chief modification in the 
face of the recorder in this equipment. The 
handwheels shown at the lower left-hand and 
right-hand corners control the vertical and 
horizontal adjustments of the plotter-bar 
“zero.” Vertical movement of the framework is 
facilitated by a counterweight which slides in a 
housing installed on the rear of the screen. 

The recorder scales and adjusters relating to 
such factors as ship’s speed, depth charge or 
projectile sinking time, and distance from the 
projector to the stern, which are incorporated 
in an actual sound range recorder, are also 
duplicated on the screen. 

Projector, Recorder Framework, and Stand 

A commercial projector (Bausch & Lomb 
Balopticon) is modified for installation over a 
sound-range recorder so that range traces ap¬ 
pearing on the recording paper are projected 
on to the screen. The modification consists of 
the removal of the lower structure normally 
used with this projector and relocation of the 
switch and blower so that the platen aperture 
can be mounted on the hinged cover of a frame¬ 
work designed to house the sound-range re¬ 
corder. The framework cover and projector to¬ 
gether are raised to a vertical position, as 
shown in Figure 6, to permit installation of the 
recorder. When the recorder is in place with its 
cover swung into the open position, also shown 
in Figure 6, the projector is lowered so that it 
fits snugly over the exposed recorder paper. 


With the projector in this position, the platen 
aperture admits an image of the upper portion 
of the recorder tracing mechanism, including 
the flyback pointer, the recording paper, and 
the short-range scale (in models in which this 
scale is not on the cover). 



Figure 6. Projector with framework cover 
opened to permit installation of recorder. 


Adjustment of the position and of the focus 
and angle of the projector are made by means 
of adjustable feet and a jack-screw arrange¬ 
ment on the stand, to bring the “zero-zero” of 
the projected recorder scales into register with 
the corresponding point on the screen. 

76 CONCLUSION 

For the purpose of instructing students in 
the maneuvers of an attacking vessel and a 


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88 


RECORDER OPERATOR TRAINERS 


submarine through the interpretation of re¬ 
corder traces, the recorder trace projector can 
be used in conjunction with the recorder of an 
antisubmarine attack teacher such as the QFA 
series underwater sound attack teachers. With 
such an arrangement, the movements of the 
submarine and of the attacking vessel on the 
QFA screen can be observed and firing time 


demonstrated in relation to the projected traces 
of the recorder. The equipment may also be 
used with the recorders of the QFL tactical 
range recorder teacher. 

Any further development work on this device 
might well be directed toward strengthening 
the projected recorder traces so that they may 
be more easily read. 


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Chapter 8 

CLASSROOM ATTACK TEACHER MODIFICATIONS 


A S laboratory developments carried on under 
. Division 6 added new or improved fea¬ 
tures to sonar gear, there was an interim need 
for devices to adapt early models of the 
Sangamo attack teacher for use with these 
features. Operator training equipment, Model 4 
(OTE-4), described in this chapter, is such an 
auxiliary device. 

Minor but useful additions made to the at¬ 
tack teacher under the program of Division 6 
are also covered here. These are the assisting 
ship projector, the attack teacher azimuth grid, 
and the depth charge pattern recorder. 



Figure 1. Diagram of OTE-4 connections with 
normalizer, attack teacher, and BDI . 


Operator Training Equipment, 
Model 4 (OTE-4) 

Operator training equipment, model 4 
(OTE-4), developed by HUSL is an auxiliary 
device for adapting early models of the Sangamo 
attack teacher for use in BDI instruction. The 
equipment generates signals suitable for direct 
application to standard BDI units and produces 
reverberation and bearing deviation indications 
that are synchronized with the audible signals 
generated by the attack teacher. It includes a 
BDI 20-kc generator whose operation is co¬ 
ordinated with that of the 0.8-kc attack teacher, 


projector simulator coils for providing right- 
left-center indications on the BDI screen, and 
a synchro-normalizer for conversion of the at¬ 
tack teacher synchro generators. 

81 INTRODUCTION 

Three units of OTE-4 were constructed to fill 
an interim need for a BDI training device to be 
used with the Sangamo attack teacher. In de¬ 
signing such a device, three principal problems 
had to be solved. First, since Models QFA-2 and 
QFA-3 of the attack teacher generate signals 
photoelectrically at 800 c, whereas the standard 
BDI is built for an input of 18 to 24 kc, it was 
necessary to design a 20-kc generator for the 
BDI and then devise some means of coordinat¬ 
ing its operation with that of the attack teacher. 
Second, a means had to be provided for pro¬ 
ducing the proper right-center-left indications 
on the BDI screen to correspond to the devia¬ 
tion of projector bearing from actual target 
bearing. Third, a synchro-normalizer was 
needed to convert the 60:1 ratio operation of 
the attack teacher synchro-generators to the 1:1 
ratio of operation of the OTE-4 unit. 

In the solution of these problems, the projec¬ 
tor simulator [PS] coils, as in other OTE de¬ 
velopments, constituted the most important 
component of the equipment. For a detailed dis¬ 
cussion of the theory of PS coils, the reader is 
referred to the section on the artificial sonar 
projector in Chapter 11 of this volume. 

Following delivery of modernized attack 
teachers with built-in BDI features, the OTE-4 
development program was abandoned. 

8 2 DESCRIPTION OF EQUIPMEN1 

OTE-4 consists of two units, one electronic 
and one mechanical. The six synchros compris¬ 
ing the normalizing device are housed in a 
special cabinet and need not be considered an 
integral part of the OTE-4, since the normalizer 
may be used to perform a similar function in 
other devices. Figure 1 shows the relationship 


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89 








































90 


CLASSROOM ATTACK TEACHER MODIFICATIONS 


of the various components when connected to 
the attack teacher. 

The mechanical unit, shown in Figure 2, 
contains the reverberation phase-and-amplitude 


All the electronic circuits, including the noise¬ 
generating and synchronizing circuits, are con¬ 
tained in the electronic unit, a functional dia¬ 
gram of which is shown in Figure 4 and a 



DIFFERENTIAL 
MOTOR SYNCHRO 
(POSITIONS PS COILS 
UNDER CHASSIS) 


ARM OF 
TRANSMITTER 


MECHANICAL 
REVERBERATION 
MODULATOR 
ASSEMBLY 


CONNECTOR 
PANEL- 


ARM OF 

TRANSMITTER 

COIL 

J 


MOTOR 


ROTARY 

CAM 


PS 

COILS 


Figure 2. Mechanical unit of OTE-4, top view. 


modulator assembly, the PS coils which simu¬ 
late bearing deviation, and the echo and rever¬ 
beration network. A circuit diagram for the 
mechanical unit is shown in Figure 3. 


schematic in Figure 5. The synthesized signals 
generated in the electronic unit are controlled 
by means of the keying pulse and echo signal 
furnished by the attack teacher, and are thus 


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DESCRIPTION OF EQUIPMENT 


91 


synchronized with the audible signals from the 
latter. 

BDI Simulation 

The relative positions of the PS coils under 
the chassis of the mechanical unit (shown in 
Figure 3) determine whether the BDI trace 


get, angle 6 in Figure 6 equals the angle be¬ 
tween projector bearing and target bearing. 

The manner in which the three inputs of pro¬ 
jector bearing, ship’s heading, and target bear¬ 
ing are combined to locate the movable PS coil 
properly with respect to the fixed PS coils will 
be described with reference to Figure 7. 


TRUE PROJECTOR BEARING 



Figure 3. Electrical schematic of OTE-4 mechanical unit. 


indicates right, left, or center bearing of the 
projector with respect to the target. The sim¬ 
plest mechanical arrangement for achieving 
realistic simulation of BDI operation with the 
use of PS coils proved to be that illustrated in 
Figure 6. The coils labeled 1, 2, and 3 are fixed 
in position; coil 4 is attached to a rotor arm so 
that, as the arm swings, this coil moves back 
and forth under the fixed coils. The circuits are 
such that when the attack teacher projector is 
exactly on center target bearing, the movable 
coil is directly under fixed coil 1 and the BDI 
trace indicates center bearing. For any other 
orientation of the projector relative to the tar- 


As far as the attack teacher is concerned, 
these three quantities are independent of one 
another. The true bearing of ship’s heading is 
obtained from the gyro repeater; the relative 
projector bearing is available in the form of a 
synchro signal generated by the rotation of the 
training wheel and bearing indicator; and the 
target’s true bearing comes as a synchro signal 
from the optical follower in the attack teacher. 
Since all synchro-generators in the Sangamo 
QFA-3 device are operated with a 60:1 ratio, it 
is necessary to employ a synchro-normalizer 
unit to convert them to a 1:1 ratio. This con¬ 
version is indicated in the part of Figure 7 


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92 


CLASSROOM ATTACK TEACHER MODIFICATIONS 


above the double-dashed line. Each of the three 
inputs actuates a synchro-motor that in turn 
drives a synchro-generator through a 60:1 gear 
train. 

The normalized gyro signal (own-ship’s true 
bearing) then feeds into the same synchro dif¬ 
ferential generator into which the normalized 
projector bearing signal is fed. The output of 

ELECTRONIC UNIT 


tion of this coil is indicated in one of the labels 
on Figure 4. The DM synchro then assumes a 
position determined by the difference between 
the two true bearings, and rotates the arm 
carrying the movable or exciter PS coil so that 
the angle 8, shown at the bottom of Figure 7, 
is the angle of deviation of the projector from 
true target bearing. This motion of the exciter 

MECHANICAL UNIT 



this differential generator, which is true pro¬ 
jector bearing, then goes to the stator windings 
of the differential motor [DM] synchro shown 
at the bottom of Figure 7. 

The normalized true target-bearing goes from 
its synchro generator to the rotor windings of 
the DM synchro shown at the bottom of Fig¬ 
ure 7. Since, however, it is necessary to avoid 
any mechanical loading of the DM synchro¬ 
rotor, the connection cannot be made directly. 
Instead the signal is transferred by the use of 
inductive coupling to a coil mounted on the end 
of the rotor shaft and coaxial with it. The loca- 


PS coil with respect to the fixed or pickup PS 
coils generates signals fed to the BDI unit. The 
trace produced in this manner on the BDI 
screen simulates accurately that encountered in 
actual service, even to the extent that no echo 
indication is obtained for angle 8 greater than 
±15°, a condition almost invariable in normal 
echo ranging. 

Reverberation Generator 

The reverberation noise amplifier, which re¬ 
ceives its signal from a 2051 gas tube, includes 
a 6SJ7 inverse time-varied gain [TVG] stage, 


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DESCRIPTION OF EQUIPMENT 


93 



Figure 5. Electrical schematic of OTE-4 electronic unit. 


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94 


CLASSROOM ATTACK TEACHER MODIFICATIONS 


a cascade-triode amplifier stage, and a cathode- 
follower output stage. The last two stages use 
the two triodes of a 6SL7 tube. From the cath¬ 
ode follower the signal goes to a mechanical 
reverberation unit. This unit consists of a 
motor-driven, irregularly notched rotary cam, 
which varies the coupling between two sets of 
PS coils. The coils and cam are shown in Fig¬ 
ure 2. The cam causes the two arms on which 



Figure 6. Arrangement of projector simulator 

coils in OTE-4. 

the transmitter coils are mounted to oscillate 
so that each transmitter coil moves in irregular 
fashion below its own pair of pickup coils. The 
two pickup coils in each set are wired in phase 
opposition; the wiring is shown at the right- 
hand side of Figure 3. 

The magnitude and phase of the voltage out¬ 
put of each set of pickup coils at any instant 
depend upon the momentary position of the 
transmitter coils. The output of one set is 
passed through a 90-degree phase-shifting net¬ 
work. One half of it is then combined in one 
direction with the output of the other coils to 
produce the reverberation input to a BDI chan¬ 
nel, whereas the other half is combined in the 
opposite direction to produce the reverberation 
input for the other BDI channel. This results in 
irregular phase variation of the input signal, 
which is already varying in amplitude because 
of the second set of coils. Thus, the output of 
the unit is two-channeled and of irregular rela¬ 
tive phase and amplitude, simulating the output 
of a split projector when excited by actual 
reverberation. 


Echo Generation 

The echo generator, which feeds a 6H6 elec¬ 
tronic keying stage, also receives its excitation 
from the 2051 noise tube. One half of the 6H6 
stage acts as an electronic switch, whereas the 
other half is used as a half-wave rectifier to 
obtain a d-c keying pulse from the 800-c echo 
pulse produced by the attack teacher. The 6H6 
stage is followed by a 6SJ7 stage arranged to 
give inverse TVG amplification. The resultant 
20-kc pulse goes to a 6SL7 tube, the first half 
of which is used as a cascade amplifier and the 
second half as a cathode follower to feed the 
PS coils. Again a two-channeled output is ob¬ 
tained. This is mixed with the reverberation 
signals by resistance-bridging networks, and 
passed on to the BDI input circuits. 

Synchronization Circuits 

Reverberation initiation of the OTE-4 unit 
has to be synchronized with that of the attack 
teacher and an echo indication must be pro¬ 
duced at the proper time to correspond to the 
audible echo generated by the attack teacher. 
The OTE-4 is connected to the attack teacher 
at the N plug on the sonar stack and obtains 
its keying pulse for the ping (which initiates 
inverse TVG) from the attack teacher’s key¬ 
ing circuits. The keying signal is a ± 145-volt 
pulse applied to the grid of a 6SL7 with both 
triodes in parallel. The triodes actuate a relay 
with two normally open contacts, one of which 
momentarily shorts the inverse TVG capacitor 
while the other applies about 60 volts to the 
BDI relay coils. The echo in the attack teacher 
occurs as a short pulse of an 800-c signal picked 
up photoelectrically from a modulated light 
source. This signal is available on the plug N 
on the sonar stack and is of the order of 1 volt 
for a reasonably loud echo. The 800-c echo 
signal passes through an amplifier consisting of 
one half of a 6SL7 tube. The output of the 
6SL7 is coupled to one half of a 6H6 to give 
half-wave rectification. The rectified output 
passes through a simple RC filter that yields a 
positive d-c pulse of about 5 volts; this voltage 
is sufficient to key the echo amplifier by neu¬ 
tralizing the fixed bias on the other half of the 
6H6, which is used as an electronic switch. 


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CONCLUSION 


95 


Propeller-Noise Generation 

A 6SJ7 noise amplifier is suppressor-grid 
modulated by the output of a 5- to 7-c oscilla¬ 
tor. This low frequency corresponds to the 
propeller throbs of a slow-speed submarine, and 
the resultant modulated noise closely simulates 
propeller noise as heard when using listening 
gear. The modulated noise is fed to the grid of 
the cathode-follower output tube of the echo 


lar to that observed in practice. Moreover, the 
propeller noise, as in actual operation, is of 
rather low intensity as compared to the echo, 
and the BDI gain has to be increased to observe 
it. 

83 CONCLUSION 

The three units of OTE-4 which were con¬ 
structed fulfilled their interim function satis¬ 


GYRO AT NORMAL IZER UNIT 

60:1 - 



ACTUALTARGET 
BEARING 


Figure 7. Functional diagram of OTE-4 synchro and PS coil systems. 


amplifier, and thence to the BDI through the 
PS coils. This gives the propeller noise, like 
the echo, a directional characteristic, making 
it appear on the BDI screen in a manner simi¬ 


factorily. Since the bearing deviation indicator 
was later included as a basic element in at¬ 
tack teacher equipment, no further work in 
this direction is recommended. 


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96 


CLASSROOM ATTACK TEACHER MODIFICATIONS 


Assisting Ship Projector 



Figure 8. Assisting ship projector. 


84 INTRODUCTION 

In an antisubmarine attack in which two 
surface ships take part, it is current practice 
for one ship only (the directing ship) to echo- 
range on the target, while the attacking ship, 
with sonar gear secured, is conned by voice- 
radio from the directing ship into the proper 
position to drop depth charges. This procedure 
requires, on the directing ship’s dead reckoning 
tracer [DRT], a simultaneous plot of the sub¬ 
marine (from sonar ranges and bearings), of 
the attacking ship (from radar ranges and 
bearings), and of the course of the directing 
ship herself. Using information obtained from 
this plot, the conning officer of the directing 
ship sends the attacking ship orders controlling 
her course, speed, and time to drop depth 
charges. 

In the training course at the West Coast 
Sound School [WCSS], two attack teachers pro¬ 
jecting images on the same screen were first 
used to simulate a two-ship attack. This make¬ 
shift arrangement had the disadvantage of 


The assisting ship projector [A&P], de¬ 
veloped by UCDWR, is designed for use in con¬ 
junction with a standard attack teacher to 
permit simulation of a two-ship attack. The 
essential components of the ASP are an optical 
projector for forming images and a control box 
upon ivhich the projector assembly is mounted. 
The instrument projects a light spot with the 
outline of a ship onto the attack teacher screen 
and, by means of an electro-mechanical system 
with appropriate controls, moves the spot 
across the screen with any desired course and 
speed. A graduated measuring line, centered on 
the ASP ship’s image and adjustable in azimuth, 
is projected onto the screen for the purpose of 
reading ranges. Bearings between the two sur¬ 
face ships may be read from a control box dial 
or a remote bearing repeater. The device can 
be used as part of any system in which a 
mechanical problem generator with projector 
is needed. 


tying up two attack teachers, thereby cutting in 
half the number of teams which could be trained 
at one time. Moreover, there was no method by 
which doppler could be introduced into the 
echoes. There was also no way of obtaining 
BDI bearings on the target. This lack necessi¬ 
tated computing center bearings from cut-ons, 
only center bearings being useful to the plot¬ 
ters. Finally, ranges of the attacking ship had 
to be measured manually. 

The assisting ship projector is designed to 
overcome all of these drawbacks. It projects on 
the screen an image representing the attacking 
ship. Only one attack teacher is needed, which 
simulates the echo-ranging (directing) ship 
and submarine in the orthodox manner. Doppler 
and BDI bearings can be obtained. The ASP 
is equipped with an optical measuring line 
centered on the attacking vessel, adjustable in 
azimuth and projected on to the screen. From 
this line ranges can be read directly. Bear¬ 
ings are indicated on a dial on the control 
box and, through a selsyn, on a remote bearing 
repeater. 


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DESCRIPTION 


97 


85 DESCRIPTION 

The equipment consists of an optical pro¬ 
jector for forming the images and a control box 
upon which the projector assembly is mounted 
(see Figure 8). The mechanism which controls 
the course and speed of the ship’s image and 
the orientation of the range-line image is 
housed inside the control box. 

The projector, the parts of which are shown 
in Figure 9, contains a lens-tube assembly with 


lamp house, hold the projector assembly, and 
the bowl, secured to the outer gimbal frame by 
means of three rods, is so placed that the drive 
wheel travels over its concave spherical surface. 
When this takes place, the projector swings in 
the gimbals, moving the images across the 
screen. 

On the front panel of the control box which 
forms the base for the projector assembly are 
three cranks and a knob (for range-line, speed, 
rudder, and initial-course control), and on a 



ship and range-line reticles in reticle cages 
which rotate in bearings; a lamp house for the 
projector lamp and condenser lenses, with 
brackets bolted to its front and back for holding 
the gears through which the reticle cages and 
the drive wheel are rotated; a tail-spindle as¬ 
sembly housing a rotating shaft which controls 
the course of the drive wheel; a motor and 
drive wheel assembly; and gimbal frames and 
bowl. The gimbals, which are pivoted to the 


subpanel are four corresponding indicating 
dials, seen through windows in front panel. The 
operation of these four controls is shown dia- 
grammatically in Figure 10 and described below. 

Azimuth Control for the Range Line. Through 
a train of gears the range crank turns a shaft 
attached by a universal joint to the gear as¬ 
sembly mounted on the front of the lamp 
house. This gear assembly in turn engages the 
spur gear on the range-line reticle cage, so that 


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98 


CLASSROOM ATTACK TEACHER MODIFICATIONS 


the range line is rotated about the ship’s image. 
At the same time the azimuth dial indicates 
the position of the range line, which is gradu¬ 
ated from 0 to 4,000 yd. 

Speed Control. The speed knob, which is 
geared to an indicator graduated in knots from 
0 to 35, regulates through a system of shafts 
and gears the output speed of the disk trans¬ 
mission mounted on the base plate (see Figure 
10). The operation of the speed-control mecha¬ 
nism moves the image on a straight course 
only. Changes in course are governed by the 
rudder control. 


by means of a shaft in the course-change mecha¬ 
nism, alters the course of the drive wheel and 
swings the ship’s reticle to the desired heading. 
In order to maintain a steady course when 
desired, without constant minor adjustments 
of the rudder crank to control yawing, an auto¬ 
matic antiyaw device is installed. 


INTRODUCTION 

Depth charge driller installations include an 
arrangement of K guns and depth charge racks 



Rudder Control. When the rudder is applied 
by turning the rudder crank, the rudder indi¬ 
cator to which the crank is geared will show 
the number of degrees of rudder applied. Two 
functions are accomplished by the rudder crank: 

(1) The ship’s speed is reduced in simulation of 
the loss of headway of a vessel in a turn; and 

(2) the course-change roller is set in motion. 
Initial-Course Control. In setting up a new 

problem, the ship’s initial course can be set by 
means of the initial-course knob. This knob, 


that are intended to simulate actual ship con¬ 
ditions as closely as possible. They are used to 
train newly organized groups of men who are 
later to act together as crews and to provide 
refresher courses for experienced men. 

When a depth charge pattern recorder is 
associated with this equipment, the firing of a 
K gun or the release of a depth charge in a 
practice drill permits an electric current to pass 
through one of eight solenoids in the pattern 
recorder. This activates the needle or electric 


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GENERAL DESCRIPTION 


99 


punch within the solenoid, forcing it upward to 
punch a hole in the paper strip moving above 
it. The electric punch is then released and drops 
back to its original position. The punched paper 
strip thus charts the simulated depth charge 
explosions and measures the ability of the crew 
to obtain a predetermined depth charge pattern. 

By adjusting the position of the eight electric 
punch assemblies and the speed at which the 
paper strip travels, it is possible to simulate 
any arrangement of K guns and depth charge 
racks on an antisubmarine [A/S] vessel travel¬ 
ing at any speed. 



Figure 11. Attack teacher azimuth grid. 


Attack Teacher Azimuth Grid 

The attack teacher azimuth, developed by 
UCDWR, is a means of projecting on the in¬ 
structor’s screen of an attack teacher a system 
of rotatable parallel lines within a fixed circular 
azimuth scale, as shoivn in Figure 11. By 
orienting the lines so that they are parallel to 
an imaginary line joining the destroyer and 
submarine images and then taking the reading 
on the azimuth scale opposite the central line, 
the instructor can ascertain the true bearing of 
the submarine target and thus check the true 
bearings reported to the conning officer by the 
sonar operator. 



Figure 12. Depth charge pattern recorder. 

Depth Charge Pattern Recorder 

The depth charge pattern recorder, de¬ 
veloped by UCDWR, is a device for recording 
the simulation of the depth charge pattern 
thrown in shore-based attack teacher exercises. 
In these exercises, the simulated depth charges 
are laid to execute a desired pattern. The re¬ 
corder supplies a scale record of this pattern 
by associating with the depth charge driller a 
number of appropriately actuated needles which 
punch holes in a moving strip of paper. The 
points at which the depth charges explode in 
relation to the path of the attacking vessel can 
then be deduced. 

8 7 GENERAL DESCRIPTION 

The depth charge pattern recorder, enclosed 
in a steel case, weighs 84 lb. Figure 12 gives a 
general view of the unit with its control panel. 

Electric Punches 

In the upper part of the recorder, directly 
under a grille across which the recording paper 
travels, is an assembly of eight solenoid-actu¬ 
ated electric punches or marker needles. This 
assembly, removed from the case, is shown in 
Figure 13. The electric punches are movable, 
so that all eight or any combination of them 
may be used. They may be screw-clamped to 
any of five support bars to conform to the posi¬ 
tions of K guns or depth charge racks on the 
A/S vessel. The five support bars (or as many 
of them as are used at one time) are held on 


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100 


CLASSROOM ATTACK TEACHER MODIFICATIONS 


two bars with beveled edges. When four screws 
are removed, it is possible to rotate the beveled- 
edge bars and the support bars through 90 
degrees, according to requirements for special 
patterns. All seven bars are marked with a 
scale arbitrarily set, so that 1/6 in. equals 
5 yd. 

Since a rigid needle might be bent by the 
drag of the moving paper or the paper would 
be torn rather than punched, each marker 



Figure 13. Electric punch assembly. 


needle is connected to its solenoid plunger by a 
hinge which enables the needle to free itself as 
the paper travels on (see Figure 14). Extra 
clamping nuts and screws and small extension 
arms are provided to make possible slight ad¬ 
justments in the positions of the needle points. 

Solenoid Circuits 

The recorder operates on 100 to 120-volt 60-c 
alternating current. From the secondary of a 
transformer which steps the voltage down to 
41 v, eight circuits lead in parallel to the eight 
solenoid coils (see Figure 15). Via terminals 
5 to 20, each of these circuits passes through a 
switch in the appropriate K gun or depth 
charge rack in the depth charge driller. When 
the power supply is on and one of these switches 
is closed, the appropriate solenoid coil actuates 
its marker needle. In addition, eight push but¬ 
tons on the front panel of the recorder parallel 
terminals 5 to 20, thus providing a means of 


actuating the solenoid needle separately for 
test or demonstration purposes, or in the event 
that one needle is used independently to mark 
the time when the conning officer gives the 
order to fire. 

Series Relay and Thermal Cutout Switch 

A series relay and a thermal cutout switch 
are provided to protect the solenoid coils from 
heat damage in case the contacts on the depth 
charge racks or K guns remain closed too long. 

When an electric punch is actuated, the relay 
armature closes a circuit through the relay 
contacts, the heat element, and the resistor R-l 
(see Figure 15). If this current continues to 
flow for about 15 seconds, endangering the 
solenoid coils, a thermo-sensitive alloy in the 



Figure 14. Construction drawing of electric 
punch. 


heating element will soften and release blades 
B-l and B-2 in the thermal cutout, thus inter¬ 
rupting the power supply to all solenoid coils. 
Resistor R-l, by limiting the current through 
the heat element, determines the length of time 


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CONCLUSION 


101 


that the current may flow before the alloy 
becomes soft. 

During the running of a pattern, each depth 
charge switch is generally closed for only a 
fraction of a second and the whole pattern can 
be run within the 15-second period. If, however, 
this period has been exceeded and the thermal 
cutout has been tripped as a result of the alloy 
softening, it is necessary to wait for the alloy 
to cool and then reset the cutout by flipping the 
cutout switch on the front panel. The series 
relay is incorporated in the circuit so that the 
15-second limit applies whether one or all eight 
of the solenoids are energized. 

Marking Paper Assembly 

A paper support bar mounted between two 
brackets is designed to hold the roll of paper, 
which is fed over two small rollers above the 
electric punch assembly, then down the side 


of the recorder in front of a bakelite platen, 
next halfway around a sprocket roller, and 
finally through a paper chute into a basket. 
While the paper is passing over the electric 
punches, it moves under a grille which, when 
a needle is actuated, holds the paper taut and 
prevents the needle from pushing it away in¬ 
stead of puncturing it. 

A Bodine fractional horsepower motor drives 
the sprocket roller which pulls the paper. The 
speed of this motor may be controlled to corre¬ 
spond to any speed of the hypothetical A/S 
vessel. 

88 CONCLUSION 

The thirty units of the depth charge pattern 
recorder which were built were widely dis¬ 
tributed in Navy schools and served as a valu¬ 
able adjunct to the depth charge driller. 


MOTOR TEST 
SWITCH 



Figure 15. Partial electric schematic for depth charge pattern recorder. 


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Chapter 9 

SHIPBOARD TRAINERS FOR SOUND OPERATORS AND ATTACK TEAMS 


S INCE SONAR operators and officers may con¬ 
tact enemy submarines only rarely after 
going to sea, shipboard drills to keep their 
skills from becoming rusty are essential. Syn¬ 
thetic methods developed to simulate echoes 
and attacks at sea are the echo injector and 
the shipboard antisubmarine attack teacher 
[SASAT], Models A and B, described in this 
chapter. Adjuncts to these devices, likewise 
covered here, are the WEA-1 and WEA-2 
adapters for SASAT-A, the SASAT slide rule, 
and the practice attack meter. 



Figure 1 . Echo injector. 

Echo Injector 

The echo injector, developed by UCDWR, is a 
simple electronic device which, when connected 
to the speaker in the sonar stack, can be used 
to produce fictitious echoes without interfering 
with the normal operation of the sonar equip¬ 
ment. Four controls on the front of the panel 
provide means for adjusting output frequencies 


from 600 to 1,000 c, for controlling the duration 
of the echo tone over the range of 35 to 250 yd 
ip water, for adjusting the intensity of the out¬ 
put signal, and for opening the power switch. 
A pushbutton at the top of the panel is used by 
the instructor to initiate the echo a suitable 
time interval after the ping has been trans¬ 
mitted. The use of the echo injector is limited 
to checking the alertness of the sound operator 
on watch at the sonar stack speaker, since the 
device does not provide exact range, doppler, or 
bearing information. 


The echo injector Model 2 is shown in Figure 
1. Of the four controls provided on the front 
panel, the knob marked “pitch” adjusts output 
frequencies from 600 to 1,000 c, with the high¬ 
est accuracy at 800 c. The knob marked “length” 
controls the duration of the echo tone over the 
range of 35 to 250 yd (in water). The knob 
marked “gain” adjusts the intensity of the out¬ 
put signal and, at the minimum intensity posi¬ 
tion, opens the power switch. A pushbutton at 
the top center of the panel is used for manually 
initiating the echo note. 

With the gain control set at a low value and 
with the pitch and length controls set at the 
desired levels, the instructor must listen to the 
pings of the sonar gear and press the push¬ 
button at the instant a real echo would be re¬ 
ceived if an actual contact had been made. 
When the controls are properly adjusted, one 
short echo tone results each time the push¬ 
button is pressed. A delay system provides that 
the button must be left in its released position 
from one-half to a full second before another 
echo can be produced. The instructor may moni¬ 
tor the echo tone before transmitting it to the 
sonar speaker by plugging a pair of headphones 
into the panel in place of the output cord. 

Circuit Design 

The electric circuit for the echo injector is 
shown in Figure 2. Tube V-101 is a triode op¬ 
erating as a positive-bias multivibrator, the 


102 


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SHIPBOARD TRAINERS FOR SOUND OPERATORS AND ATTACK TEAMS 


103 


frequency of which increases as the bias voltage 
applied to the grids is increased. The relative 
values of plate load resistance and cathode bias 
resistance are so chosen as to provide a sub¬ 
stantially linear frequency response with re¬ 
spect to grid bias voltage in the upper part 
of the operable frequency range of the 
multivibrator; values of feedback capacity 
(0.0016 pf) and grid leak (1 megacycle) are 
so chosen as to keep the nonlinear frequency 


the voltage drop across it and so permits an 
adjustment of the number of volts change of 
grid bias obtained by a given rotation of the 
pitch control knob. 

The multivibrator drives an output stage 
which uses the beam power section V-102A of 
V-102. A 1-megohm resistor in series with the 
control grid of this power tube prevents the 
output stage from imposing enough load on the 
multivibrator to affect the frequency. Normally, 



range below the range required of the echo 
injector. The expected variation in character¬ 
istics of the 12SL7 vacuum tube used here will 
not upset this linearity of the frequency re¬ 
sponse but will affect the frequency sensitivity, 
that is, the number of cycles per second that the 
frequency changes for a given change in grid 
bias voltage. This expected variation in fre¬ 
quency sensitivity between different tubes is 
compensated by an alignment control which 
consists of a 15,000-ohm rheostat connected in 
series with a 100,000-ohm potentiometer that 
constitutes the grid bias potentiometer. This 
alignment rheostat changes the current through 
the pitch control potentiometer and therefore 


the output stage is biased below cutoff because 
the cathode is held at approximately 70 volts 
positive by a voltage divider circuit consisting 
of two 20K resistors. For transmitting an echo 
tone, the lower one of these resistors is short- 
circuited by means of a keying relay, thereby 
bringing the cathode to zero potential (with 
respect to the B supply). A 2-pf condenser is 
placed in shunt with this resistor to eliminate 
the “pop” that would otherwise occur at the 
end of the echo tone. A 10-ohm resistor in 
series with the relay contacts prevents the dis¬ 
charge from the condenser from injuring the 
contacts. 

The gain, or output intensity, is controlled 


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104 


SHIPBOARD TRAINERS FOR SOUND OPERATORS AND ATTACK TEAMS 


by the screen voltage of the output stage. The 
output transformer has an impedance ratio of 
2,000:6 to match a 6-ohm load and delivers a 
maximum output of 2 watts. A 0.02-jxf con¬ 
denser across the primary of the output trans¬ 
former rounds off the square wave from the 
multivibrator to improve the realism of the 
tone. 

The power supply consists of a half-wave 
rectifier using the rectifier section of V-102 
with a 50-|if condenser for a filter. The keying 
control employs a pushbutton microswitch, a 
25-|xf condenser, and a relay. Normally, the 
microswitch connects the 25-p.f condenser to the 
power supply for charging it. When the push¬ 
button is depressed, the switch disconnects the 
charged condenser from the power supply and 
connects it across the relay coil. The discharge 
of the condenser through the coil causes the 
relay to close its contacts momentarily so that 
the output tube V-102A transmits an echo tone. 
An adjustable shunt consisting of a 400-ohm 
fixed resistor in series with a 10,000-ohm rheo¬ 
stat shortens the time that the relay contacts 
are held closed. A 10,000-ohm resistor is in¬ 
cluded in the circuit through which the con¬ 
denser is charged so as to impose a delay be¬ 
tween successive echo tones. The imposition of 
a time delay between successive echoes is in¬ 
tended primarily as a precaution against acci¬ 
dental double echoes. 



Figure 3. (SASAT-A), Model IV. 


Shipboard Antisubmarine Attack Teacher 

The shipboard antisubmarine attack teacher 
[&4&4T-A], developed by the University of 
California, Division of War Research, at the 
U. S. Navy Radio and Sound Laboratory, San 
Diego, California, is a small portable device 
for introducing into shipboard QC echo-ranging 
equipment artificial echoes realistically simu¬ 
lating the conditions of an antisubmarine attack 
run. The echo injected can be so controlled as to 
indicate a submarine lying motionless, moving 
in any direction, changing course, remaining at 
a constant speed, altering speed, approaching 
the destroyer or moving away from it. By means 
of such controls, the destroyer conning officer 
can plan and conduct a practice attack, as well 
as drill sonar operators in making and develop¬ 
ing a contact, determining bow cut-ons and 
target angles, estimating range and range rate, 
detecting evasive submarine maneuvers, and 
going through lost-contact procedures. 

91 INTRODUCTION 

SASAT-A was developed to provide sonar 
operators with practice at sea in detection of 
echoes and the use of the tactical range re¬ 
corder. At the same time, it affords the conning 
officer practice in attacking evading enemy sub¬ 
marines. Since it is small, it may be left per¬ 
manently connected to the echo-ranging gear 
of a ship and switched into action for sonar 
team practice at any time. When the SASAT 
is operating, the echo-ranging gear is essen¬ 
tially unaltered and continues to transmit sig¬ 
nals and receive water noise and real echoes, 
if any. 

As with echoes from a real target, those 
produced by the SASAT can be heard on the 
sonar loudspeaker, and can be translated into 
traces on the tactical range recorder to indi¬ 
cate range, range rate, and approximate target 
angle. 

The SASAT-A is not entirely satisfactory as 
a training device because skill and familiarity 
with relative motion is required of the operator 
who sets the problem. Although he may use the 
instructor’s manual, which furnishes complete 
instructions with tabulated charts and sketches 


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CIRCUIT DESCRIPTION (MODEL IV) 


105 


for various kinds of training from simple dop- 
pler drills to highly complex runs involving 
the entire sonar team, the degree of realism 
achieved in the exercise depends primarily on 
his quickness in coordinating range rate, dop- 
pler, and echo length and intensity throughout 
a changing situation. A special SASAT slide 
rule, described elsewhere in this chapter, was 
developed to offset this difficulty by giving the 
range rates and the relative bearings of a sub¬ 
marine to a destroyer as functions of the dis¬ 
tance between them. The experimental SASAT- 
B, incorporating an automatic problem gen¬ 
erator, was therefore designed as a further 
improvement. SASAT-B is described in a later 
section. 

WEA-1 and WEA-2 adapters, described later 
in this chapter, were designed so that SASAT- 
A could be used at Small Craft Training 
Centers on the type of sound equipment in¬ 
stalled in small boats. 


92 GENERAL DESCRIPTION 

SASAT-A, Model IV, which served as the 
manufacturer’s prototype, is shown in Figure 
3. A line switch controls all leads into the echo¬ 
ranging gear. An echo output switch is used to 
monitor the echo so that it may be modified, 
if necessary, by the instructor, who listens with 
headphones plugged into the phone jack. When 
this switch is in the test position, the echo is 
heard only by the instructor, and when in the 
on position by both the instructor and the 
operator of the sonar equipment. A range dial 
controls the time between the signal sent out 
by the echo-ranging gear and the echo injected 
by the SASAT. A range-rate dial, automati¬ 
cally controlling the range dial, increases or 
decreases this time interval according to the 
range rate selected for the exercise. An echo 
length control determines the duration of the 
echo, so that short echoes can be used for beam 
attacks and longer ones for stern or bow at¬ 
tacks. The amplitude of the echo is similarly 
controlled by an echo loudness dial for near 
and far targets. A doppler dial controls pitch, 
and concentric bearing dials enable the instruc¬ 
tor to indicate own-ship’s true bearing course 


and set target relative to bearing. In addition, 
provisions are made within the apparatus for 
automatically increasing the target width as 
the range decreases and attenuating the echo 
at what would conform to the bearings of the 
right or left cut-ons. 

A later experimental model of SASAT-A, 
Model V, incorporated modifications making 
the device usable with the BDI, and included a 
synchro-powered true bearing dial coupled to 
the ship’s gyro. Dual signals were generated 
in Model V to simulate signals produced by a 
split projector. Moreover, the signals were gen¬ 
erated at adjustable supersonic frequencies 
directly applicable to BDI and were delivered to 
the sonar equipment at the projector terminals. 
Model IV, on the other hand, generated echoes 
at audio frequencies and delivered them to the 
first audio stage in the QC receiver. 


93 CIRCUIT DESCRIPTION (MODEL IV) 

The keying of the relay which operates the 
transmitter in the echo-ranging apparatus is 
also utilized to activate a relay in the SASAT. 
After a time determined by the setting of its 
controls, the SASAT introduces into the audio 
system of the echo-ranging gear a simulated 
echo signal which can be detected by the sound 
operator if his projector is trained in a direc¬ 
tion corresponding to the setting of the target¬ 
bearing dial on the SASAT. 

The circuits governing these operations may 
be conveniently divided into six sections as in¬ 
dicated in the dotted-line boxes shown in the 
wiring schematic, Figure 4. These are the echo 
oscillator, the bearing control, the echo delay 
and keying, the output, the power supply sec¬ 
tions, and the terminal strip connections. 

Echo Oscillator Section 

The simulated echo signal is developed in a 
resistance-capacitance stabilized oscillator V-l, 
with the oscillator frequency determined by 
the RC circuit consisting of capacitors C-9 and 
C-10 and a dual potentiometer P-8 and limited 
at the upper frequency by resistors R-23 and 
R-24. These resistors, together with the potenti¬ 
ometer P-9 and the thermistor S-ll, form a 


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106 


SHIPBOARD TRAINERS FOR SOUND OPERATORS AND ATTACK TEAMS 



4 ) 

TT 

C 


< 

EH 

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m 

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Si 

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CIRCUIT DESCRIPTION (MODEL IV) 


107 


bridge. The ratio of the resistance of the po¬ 
tentiometer P-9 to that of the thermistor S-ll 
determines the transmission at the resonant 
frequency. Since an increase in voltage causes 
a decrease in the resistance of the thermistor 
and therefore a decrease in the output of the 
bridge, the thermistor regulates the amplitude 
of the oscillation and thereby tends to stabilize 
the frequency of oscillation. The adjustability 
of the resistor P-9 permits the automatically 
maintained amplitude to be fixed at a desired 
value. The output transformer T-4 is provided 
with two secondary windings, one exciting the 
bridge, the other constituting part of a push- 
pull output circuit. 

Bearing Control 

For proper operation of the SASAT, it is 
necessary to have a control device which will 
function with the selsyn system of the echo¬ 
ranging gear. The wires between the trans¬ 
mitting and receiving selsyns of this system 
carry information determined by the particular 
direction in which the projector mechanism is 
trained. 

These voltages from the echo-ranging gear 
are supplied to the SASAT through a multi¬ 
plier and the corrective resistors R-37, R-38, 
and R-39 to the ring potentiometer S-14. The 
rotating arms on the ring potentiometer, which 
are used to determine the potential at points 
180 degrees apart, supply their output voltage 
through the transformer T-3, the voltage di¬ 
vider P-2, the resistor R-27, and the isolating 
resistor R-19 to the grid of the echo-modula¬ 
tor bias rectifier V-4. This tube acts as a 
delayed type rectifier in which the delay is con¬ 
trollable by the initial bias supplied by the 
potentiometer P-11. The output of V-4 sup¬ 
plies grid bias to tubes V-2 and V-3. A hum 
filter consisting of the condensers C-7 and C-8 
and the resistor R-15 is inserted between tube 
V-4 and transformer T-4. 

When the arms of the potentiometer S-14 are 
set in one position conforming to one position 
on the SASAT relative bearing scale, voltage 
will appear across them at all times except 
when the sound operator has trained his pro¬ 
jector to the same bearing. At this time, no 


current will flow in tube V-4; furthermore, 
since V-4 controls the output section, the modu¬ 
lators V-2 and V-3 in that section will supply 
an echo signal to the audio section of the 
echo-ranging gear receiver. 

When there is a slight difference between the 
bearings set on the SASAT and those on the 
echo-ranging gear, no effects will be observed 
because of the bias maintained by the potenti¬ 
ometer P-11, and the echo will still be heard. 
If there is a large difference, tube V-4 will 
begin to pass current, the potential at terminal 
6 on T-4 will fall, and the transmission of the 
balanced modulator will be decreased, until 
finally the transmission of the modulator will 
drop to zero and no echo will be heard. 

When the output signal is transmitted, cur¬ 
rent which operates the loudspeaker cutoff or 
meeting relay in the echo-ranging gear also 
actuates the SASAT relay S-13, which is con¬ 
nected to the thyratron V-6 and the delay cir¬ 
cuit charging tube V-5. When relay S-13 is 
operated, the condenser C-l is discharged to 
essentially zero voltage through the peak- 
current limiting resistor R-l, and tube V-6 is 
extinguished as its plate circuit is opened by 
additional relay contacts. As relay S-13 is 
released, condenser C-l starts to charge at a 
rate determined by the charging current in 
tube V-5 and potentiometer P-1. This action 
proceeds until the grid of tube V-6 becomes 
sufficiently positive with respect to the ground, 
so that tube V-6 fires. Tube V-6 will continue 
to conduct until relay S-13 is again actuated 
by the transmitted pulse. 

At the time of firing, the cathode of tube V-6 
jumps positive because of the trigger action of 
the tube’s gas content. This sudden rise is 
suitably shaped by the network comprising the 
resistors R-5 and R-ll and the condensers C-2 
and C-3, so that a pulse is available a con¬ 
trollable time after the release of relay S-13. 
This delay corresponds to the delay between 
ping and echo, which measures the range of 
the target in normal echo-ranging procedure 
and is controlled by the value of the resistor P-1. 

The keying pulse is finally supplied to a 
single-pulse multivibrator consisting of the two 
tubes making up V-7, the resistors R-7, R-8, 


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108 


SHIPBOARD TRAINERS FOR SOUND OPERATORS AND ATTACK TEAMS 


R-9, R-10, and P-5 and the condenser C-4. It is a 
standard flip-flop multivibrator which, at the 
introduction of an input positive pulse pro¬ 
duces an output pulse whose length is con¬ 
trolled by the charging time constant of a 
condenser C-4 and of resistors R-9 and P-5. 

The keying pulse is supplied to the screens 
of tubes V-2 and V-3 through the network 
comprising the resistors R-12 and R-13 and the 
condensers C-5 and C-6. This network takes 
the high-frequency component out of the lead¬ 
ing and lagging edges of the keying pulse and 
thus avoids the presence of “keying clicks” in 
the simulated echo signal. A synchronous motor 
which drives three potentiometers, P-1, P-2, 
and P-3, automatically adjusts echo amplitude 
and target width for range. A friction drive, 
adjustable by the range-rate control dial on 
the front panel, governs the speed at which 
the potentiometers rotate. P-1 controls the 
delay between signal and echo, thus increasing 
or decreasing the range according to the range 
rate selected, P-2 modifies the width of the 
relative bearing band over which the echo may 
be detected, and P-3 affects the amplitude of 
the echo. 

Output 

The output of the echo amplitude-modulator 
tubes, V-2 and V-3, drives the transformer 
T-5 and the attenuator P-3. This output circuit 
is connected to the audio stage of the echo¬ 
ranging gear receiver. As the keying potential 
applied to the screen grids of V-l and V-2 ap¬ 
proaches that of the plates, transmission occurs 
with a strength governed by the amplitude 
control P-7, which acts as a self-bias resistor, 
and the potential of the grid bias. The adjust¬ 
able voltage divider P-6 serves to balance the 
modulator against any relative deviation of the 
characteristics of tubes V-2 and V-3. 

Power Supply 

The SASAT requires a power supply with 
constant d-c voltage output over a wide range 
of a-c input voltages. For these reasons the 
SASAT’s power supply is of a regulated type. 

SASAT-B was developed primarily to over¬ 
come the disadvantage of the series of manu¬ 
ally operated controls characteristic of SASAT 


A. The simulated target is maneuvered by 
means of rudder and speed controls which pro¬ 
vide automatically generated ranges and bear¬ 
ings, and a chart continuously shows the 
instructor the relative positions of ship and 
target together with ship’s course. The dop- 
pler, attenuation, and other effects in the echo 
are also automatically introduced. Model I 
performed effectively in sea tests. Model II, 
which was intended to incorporate a number 
of improvements, was partially designed but 
had not reached the construction stage when 
the project was discontinued. 



Figure 5. SASAT-B, Model I, Submarine oper¬ 
ator’s station. 


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GENERAL DESCRIPTION (MODEL I) 


109 


Shipboard Antisubmarine Attack Teacher 

The shipboard antisubmarine attack teacher 
[SASAT-B] is an improved version of 
SASAT-A with automatic problem generator 
features which make it less dependent for its 
effectiveness on the skill of the operator than is 
the manually controlled SASAT-A. Like 
SASAT-A, it is a portable instrument which 
introduces artificial echoes into QC echo-rang¬ 
ing gear for use in practice attack drills at sea. 
In operation, a simidated target is maneuvered 
by means of rudder and speed controls which 
provide automatically generated ranges and 
bearings. The doppler shift, attenuation, and 
other effects in the echo are also automatically 
introduced. Model I is housed in a metal cabinet 
with two control panels on opposite sides of the 
instrument. On the instructor’s panel are in¬ 
dicators for target course and bearing, “depth 
charge” firing controls, explosion indicators 
and a large polar “scoring chart” which shows 
relative position of the target and attacking 
ship. By means of this chart, analysis of the 
final stages of an attack becomes possible. On 
the other panel, designed for an assistant or 
“submarine operator,” are a submarine speed 
scale, a rudder and a depth control for use in 
conning the target, and a large polar chart 
showing the attacking ship’s position relative 
to the target. Unless evasive maneuvers are re¬ 
quired, an assistant is not needed; the controls 
on this panel can be preset to obtain any desired 
nonmaneuvering target course. The SASAT-B 
development tvas carried on by UCDWR. 


of the explosive charges when these are of the 
contact type. 

If, on the other hand, the target is to engage 
in evasive tactics, an operator must man the 



94 GENERAL DESCRIPTION (MODEL I) 

SASAT-B (Model I) is contained in a metal 
cabinet with two opposing panels. The panel 
designated as the submarine operator’s sta¬ 
tion is shown in Figure 5. If the target is to 
follow a steady course, no operator is required 
at this station. The dials marked N-S preset 
and E-W preset are used to set the course, 
target speed is preset on the submarine speed 
scale, and target depth on the depth scale. The 
depth control determines the minimum range 
at which the echo is lost and the sinking time 


Figure 6. SASAT-B, Model I, instructor’s 
station. 

controls at the submarine operator’s station. 
He uses the submarine speed scale and the sub¬ 
marine rudder for conning the target. The 
polar chart in the center of his panel shows 
the submarine’s course as a heavy line, and a 
pair of intersecting lines shows the position of 
the attacking vessel relative to the submarine. 
Range is marked off in 500-yd intervals to cor¬ 
respond to the rough estimate of range which 
a submarine sound operator can make. At the 
top of the panel is a pair of lights. Illumination 
of the red light represents the explosion of a 


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110 


SHIPBOARD TRAINERS FOR SOUND OPERATORS AND ATTACK TEAMS 


depth charge, and the green light glows when 
a contact charge has reached the submarine’s 
depth. 

The opposite side of the instrument, shown 
in Figure 6, is the instructor’s station. The 
dials on this panel indicating submarine course 
and relative bearing are for reference only 
and should be kept invisible to the sonar opera¬ 
tors and sound officers. In the center is a scor¬ 
ing chart similar to the one on the submarine 
operator’s panel, except that in this case the 
destroyer’s course is shown by the single heavy 
line (with the sound projector presumed to be 
at the center), and the relative position of the 
target is shown by the two intersecting lines. 
This chart, however, shows only the last 800 
yd of the attack run and is used principally 
for evaluation. When a depth charge is re¬ 
leased, the corresponding red light appears. 
An arrester or “memory” mechanism within 
the instrument removes the drive to this scale 
which comes from the maneuvering mechanism 
corresponding to the ship. Then, after a time 
corresponding to the depth charge setting which 
is made by the instructor, the red light marked 
“explosion” glows and the cross hairs stop 
completely. By comparing the position of these 
cross hairs with the position which they should 
occupy for a successful attack it is possible to 
measure the error in yards. 

In the case of a contact charge, the green 
lights appear; the operation is identical except 
that it is the submarine’s depth which controls 
the sinking time instead of the depth charge 
setting. At the top of the instrument is a re¬ 
lease button which releases all the arresters 
and places the cross hairs in the position which 
they would have if an attack had not been com¬ 
pleted. This is in order to make a reattack, if 
desired, without disturbing the maneuvering 
position. 

There are also knobs for adjusting echo 
length and loudness and for correcting the fre¬ 
quency. Frequency correction for own-ship’s 
doppler and for target doppler are automatic. 
The knob is used only for occasional adjust¬ 
ment. 

When the ship has been maneuvered into a 
suitable attack position, the officer in charge 


of the attack may release a fire button which 
is located on a small box connected to the in¬ 
strument by cable. This box also carries a 
knob for monitoring the ship’s speed, so that 
the mechanism within the instrument will rep¬ 
resent the ship’s speed correctly at all times. 
The control box also carries a switch for shift¬ 
ing from contact charges to depth charges. 

This machine was designed for a sinking 
time in seconds, as shown on the depth charge 
setting. It may thus be used with any type of 
depth charge. In the case of the contact charge 
this model was designed for mousetrap attack 
with the corresponding time of flight and a 
sinking time of 25 fps. 

Mechanical Details 

Figure 7 is a mechanical schematic showing 
the function of the mechanical parts. The 
maneuvers of the ship and target are applied 
to a pair of ball-type component resolvers. 
Northings and eastings from the ship’s re¬ 
solver are subtracted from those of the target’s 
resolver and the difference is fed to the scales; 
it is also fed to a mechanism which is used for 
controlling the range and bearing of the echo. 
The echo range is effected by varying a re¬ 
sistance with a chain-operated potentiometer. 
The bearing of the echo is determined by a 
disk on which a lobe-shaped commutator is 
installed which engages the contact that repre¬ 
sents the target. 

The relative bearing is fed into the instru¬ 
ment from a selsyn generator mounted on the 
ship’s QC training mechanism. The selsyn 
motor within the instrument supplies this bear¬ 
ing to a differential which adds it to the ship’s 
course supplied from a compass repeater; the 
output of this differential is the true bearing 
of the projector. This is applied to the scales 
and the ranging disk. It is also applied to an¬ 
other differential, together with the submarine’s 
course. The output of this differential supplies 
target angle which is used to control the target 
doppler. 

The ball component resolvers have proved to 
be a very satisfactory and simple means of 
analyzing the maneuvers. They are driven by 


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GENERAL DESCRIPTION (MODEL I) 


111 


permanent-magnet motors for speed-control 
purposes, the voltage of which is adjusted by 
the speed-control knobs. Another permanent- 
magnet motor supplies the turning of the sub¬ 
marine and has impressed on it the same volt¬ 
age as the submarine’s speed motor. 

Each arrester used for scoring contains a 


of rollers. The appearance of the chart is such 
that these crosslines appear to be drawn on the 
rotating course chart which is mounted behind 
them (see Figure 5). The same mechanism is 
used for both the submarine operator’s chart 
and the scoring chart. Take-up springs of the 
type used in window shades absorb all back- 



Figure 7. Mechanical schematic for SASAT-B, Model I. 


pair of springs, which are preloaded to main¬ 
tain a central position, and a clutch of the mag¬ 
netic plate type. These arresters also have a 
threaded section for counting the number of 
turns lost, in the event the shaft travels more 
than one turn during scoring. 

A mechanism is used in conjunction with the 
charts to present the position of the target as 
an intersection of a pair of lines at right angles. 
Each of these lines is painted across a sheet 
of cellulose nitrate which is mounted on a pair 


lash and the mechanism proves to be accurate. 
It is much more compact than an equivalent 
optical system and is also free from trigo¬ 
nometric error. 

The position at which echo is lost is con¬ 
trolled by a microswitch actuated by two cams, 
one on the submarine depth shaft and the other 
on the range shaft. These cams are so designed 
that it is possible to hear an echo at long 
ranges, but the echo is lost at short ranges, 
the point at which it is lost being determined 


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112 


SHIPBOARD TRAINERS FOR SOUND OPERATORS AND ATTACK TEAMS 


by the submarine’s depth. A telechron motor 
is used for timing the intervals between release 
and explosion. 

Electrical Details 

The echo simulator employed in Model I is 
designed for use in conjunction with own-dop- 
pler nullifier [ODN] equipment. The echo seems 
to be more closely simulated by the output of a 
positive bias multivibrator than by that of a 
pure wave oscillator. A multivibrator oscilla¬ 
tor is, therefore, used as an echo generator, 
the frequency of which is controlled by the 
voltage drop across a bridge circuit, R-3 and 
R-4 of Figure 8. This voltage is a function of 
target angle and target speed and varies the 
frequency of the echo generator over the target- 
doppler range. A panel adjustment, R-34 of 
Figure 8, varies the base frequency of the echo 
generator so that it may be matched to the 
beat frequency of the QC receiver at zero dop- 
pler. After this initial adjustment has been 
made, target-doppler variations are automati¬ 
cally made. 

V-8, V-9, and V-10 (Figure 8) comprise the 
echo delay and timing circuit. This circuit is 
actuated by a relay energized from the same 
source as the QC ping relay. This relay, S-l, 
deionizes V-9 and discharges C-5 while the 
ping is transmitted. When the contacts open at 
the end of the ping transmission, C-5 charges 
through V-8 at a rate determined by the resist¬ 
ance of R-15. The latter is varied mechanically 
by target range. When the charge across C-5 
reaches the ionizing potential of the thyratron 
V-9, the latter fires, applying a positive po¬ 
tential to the grid of the trigger circuit V-10. 
As a result, a relatively high current flows 
through R-21 and R-22. Inasmuch as R-21 is 
common to both halves of V-10, this current de¬ 
velops a bias, causing the current in R-23 to fall 
to zero. The voltage drop across R-23 deter¬ 
mines the cutoff bias of the keyed amplifier, 
V-12 and V-13. Consequently, when this bias is 
removed, the keyed amplifier passes the multi¬ 
vibrator output. Echo length is determined by 
constants of the circuit, comprising C-8, R-22, 
R-24, R-25, and controlled by R-25. 

The output of the keyed amplifier is roughly 
attenuated by R-37 and then fed to a probe 


disk attenuator, which further reduces the out¬ 
put voltage commensurate with range and pro¬ 
jector bearing. 

It will be noted from Figure 8 that Model I 
includes the use of a selsyn motor M-2 to trans¬ 
mit projector bearing to the equipment. The 
remote selsyn generator is mounted on the pro¬ 
jector hoist column. (This practice is avoided 
in Model II because of difficulties encountered 
in running cables between decks on ship in¬ 
stallations.) 

When a charge is fired, the fire button is 
closed, performing the following functions. 

1. Solenoid L-l releases a synchronous timer 
motor, causing a cam to rotate a 1 rpm. 

2. Destroyer brakes L-2, L-3, and L-4 are 
energized, isolating the motion of the destroyer 
from the scoring chart. 

3. Relay X-l is closed, lighting pilot lamp 
1-6, red, or 1-5, green (depth or contact charge 
respectively). 

The timer motor referred to above is electri¬ 
cally connected at all times, but its motion is 
halted by the solenoid arm. When the timer 
motor is released, the rotating cam engages 
either S-4 or S-5, depending on position of 
choice switch. The position of S-4 is adjusted 
in accord with the depth of submarine dial, 
while the position of S-5 is adjusted in accord 
with the time control on the released depth 
charge. When the cam contacts S-4 or S-5, co¬ 
incidental with the hypothetical explosion, the 
following functions are performed. 

1. L-5 and L-6 are energized, subtracting the 
motion of the submarine, thus indicating the 
position of the submarine when the charge ex¬ 
ploded or reached the depth of the submarine. 

2. X-3 is closed, lighting pilot lamps 1-2 and 
1-4, red, or 1-1 and 1-3, green. 

S-l and S-2 are limit switches designed to 
open when the problem runs off the screen. 

Z-l is a selenium cell full-wave rectifier, 
supplying a permanent-magnet [PM] field, d-c 
motor M-4 which furnishes destroyer speed 
information to the ball solver described in the 
mechanical review. Its speed is governed by a 
remote Variac located on the bridge of the 
vessel. 

The submarine speed is furnished by a similar 
motor M-5, and controlled by a Variac V via 


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GENERAL DESCRIPTION (MODEL I) 


113 



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Figure 8. Electrical and echo simulator schematic for SASAT-B, Model I. 




































































































































































































































































































































114 


SHIPBOARD TRAINERS FOR SOUND OPERATORS AND ATTACK TEAMS 


a second selenium cell rectifier Z-2. A third 
PM field motor M-6 is connected in parallel 
with M-5 through a reversing switch for rudder 
information. By this means the submarine can 
be conned, its turning rate being proportional 
to its speed. A flywheel makes the action 
sluggish in accord with actual conditions. In 
the off position M-6 acts as a generator, the 
output of which is shorted to achieve a braking 
effect. 

Z-3 furnishes a voltage to four potentiometers 
which produce the voltage for controlling own- 
doppler frequency. 


95 GENERAL DESCRIPTION (MODEL II) 

Although Model II of SASAT-B remained in 
the design stage, it is believed that a number 
of valuable improvements were projected which 
should be considered in any future develop¬ 
ment. 

This model in general is simpler, since it is 
designed for one-man operation. The two op¬ 
posing panels of Model I had sometimes been 
found inconvenient for installation on ship¬ 
board. It seemed quite feasible for the instruc¬ 
tor to maneuver the target in addition to his 
other duties, and Model II therefore has only 
one control panel. In the scoring on this in¬ 
strument it was likewise decided not to include 
the arrester mechanism. The scoring may be 
done so rapidly that it was felt that an in¬ 
significant time would be lost and that, in 
bringing ships about for a reattack, there would 
be a negligible error. 

Other simplifications were envisaged in the 
form of additional automatic features. It was 
expected to include the characteristic effects 
on the bearing deviation indicator [BDI], 
where such equipment was part of the echo¬ 
ranging gear. A doppler control of the sonic 
speedometer type was planned, so that rever¬ 
berations would govern the speed of the virtual 
attacking ship within the instrument and, at 
the same time, render the doppler automatic. 
(For a discussion of the various methods of pro¬ 
ducing doppler effects in the simulated echo, 
see the bibliography. 1 ) The echo length would 
have been made to vary automatically with 


changes in ping length and target angle. To 
simulate the error in the indicated range on 
the range recorder during stern attacks, it was 
planned to couple a range compensator to the 
shaft which varies the target doppler in ac¬ 
cordance with target angle variations. 

Figure 9 shows the control panel designed 
for Model II. The ship is at the center of the 
12-in.-sq chart, and its course is represented 
by the heavy black line which crosses the chart. 
On an outer ring which rotates with this line, 
relative bearings may be read. True bearings 
appear on an inner azimuth ring engraved on 
the back of the transparent window. Target 
position is shown at the intersection of a pair 
of crosslines, and projector bearing is repre¬ 
sented by a lobe-shaped pointer, with range 
graduations, painted on a transparent disk. 

This projector bearing pointer may be “bor¬ 
rowed” by the instructor, using the knob 
marked indicator, whenever he wishes to meas¬ 
ure target range and bearing, as, for example, 
at the moment of “fire one.” At the same time, 
as part of the scoring, he can record the courses 
and speeds of the vessels while pressing the 
release button so that the maneuvering may 
continue within the instrument. Except when 
the indicator knob is on, the projector bearing 
pointer is controlled through a selsyn-line in¬ 
terconnector by the sound operator as he trains 
his projector. 

On the lower part of the panel are the 
conning controls and dials for monitoring the 
ship’s speed. The latter are used for conning 
the instrument’s hypothetical ship separately 
from the real ship, if this should be desired 
temporarily in preference to maneuvering the 
real ship. Knobs are also provided for occasional 
correction of echo frequency, length, and loud¬ 
ness, features which are automatic during 
actual operation. 

Mechanical Details 

Figure 10 is a schematic showing the func¬ 
tional operation of the mechanical components 
in Model II. The same type of component 
analyzer is employed as that used in Model I 
except that the mechanism is driven by a 
synchronous motor through variable speed 
controls. This is done so that a high degree 


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GENERAL DESCRIPTION (MODEL II) 


115 


of linearity in the speed control will be present Shown in the schematic at M is a motor for 
since it is desired to employ this in connection varying own-ship’s speed. It is intended that 
with the doppler control. this motor be controlled by a frequency dis- 



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116 


SHIPBOARD TRAINERS FOR SOUND OPERATORS AND ATTACK TEAMS 



(DOPPLER) ERROR-IN-RANGE CHANGE 
POT POT 

Figure 10. Mechanical schematic for SASAT-B, Model II. 


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GENERAL DESCRIPTION (MODEL II) 


117 


criminator circuit so that in producing a base 
oscillator frequency, which matches the rever¬ 
beration frequency in the water, the motor 
will at the same time measure the speed of the 
actual attacking ship and correct the virtual 
attacking ship’s speed to the same value. 

Instead of the chain-drive potentiometer used 
in Model I, a much simpler ranging mechanism 
has been developed. The northing and easting 
outputs from the resolvers drive Variacs, while 
the bearing mechanism drives a differential 
selsyn. The relation of these Variacs to the 


ating the mechanism. The only connections 
which are made to the ship’s gear are the con¬ 
nections to the training selsyn, the compass 
selsyn, and the sound gear itself. It was hoped 
that this system would take care of the auto¬ 
matic speed control of the virtual attacking 
ship without making additional connections 
to pitometers and other components. 

Electrical Details 

In the proposed echo-simulating unit of 
Model II, a sonic speed control system was to 



Figure 11. Sonic speed control as a doppler compensator. 


selsyn which controls the echo is described in 
connection with the electrical details. This 
method was tested experimentally in its de¬ 
tails, and seems to give great promise in simpli¬ 
fying the mechanical construction by eliminat¬ 
ing the rather bothersome echo mechanism 
employed in Model I. 

It was desired to make only electric connec¬ 
tions to the ship from the instrument, and for 
this and other reasons control transformers 
and servo-motors are shown in this design for 
minimizing the amount of current drawn from 
the selsyn lines on the ship and, at the same 
time, for developing sufficient torque for oper- 


be employed. In this system, own doppler is a 
direct function of the projector relative to 
bearing and the speed of the ship. The latter 
is difficult to determine accurately because of 
the number of variable factors involved. The 
sonic speedometer, however, shows promise of 
achieving an accurate result from own-doppler 
variations represented in water reverberations. 
At the same time it introduces own-ship’s speed 
to the instrument’s integrating mechanism. 

In this system, as shown in Figure 11, a volt¬ 
age-sensitive oscillator F. 2 is mixed with F a and 
F 1 to form F r — ( F 2 + F 3 ), which is applied 
to a discriminator tuned to F 4 . The polarized 


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118 


SHIPBOARD TRAINERS FOR SOUND OPERATORS AND ATTACK TEAMS 


output of the discriminator is utilized to con¬ 
trol a reversible motor driving a potentiometer 
R-l. The rotational displacement of R-l from 
a zero position is made proportional to ship’s 
speed and a dial connected to the potentiometer 
shaft reads ship’s speed. (At the same time, 
this motor controls the speed of the virtual ship 
within the instrument.) 

Again in Figure 11, E-l is applied to a bridge 
circuit consisting of R-2 and R-3. R-2 is a 
center-tapped resistor, while R-3 is a poten¬ 
tiometer varied in accordance with the cosine 
of the relative projector bearing. 

During the reverberation sampling period, 
relay S closes, performing the following func¬ 
tions. 

1. Circuit consisting of R-l, R-2, and R-3 
produces a voltage E-l, which is applied to the 
voltage-sensitive oscillator, F 2 . 

2. Direct current output of the discriminator 
is applied to the motor control. 

Normally with the ship running at a constant 
speed, a variation of E-2 by R-3 will cause the 
same frequency displacement in F, as in F x 
(A F x = AF 2 ), and the corrected component F x 
— ( F 2 | F 3 ) = F 4 . However, if the ship’s 
speed changes between ping samples, A F x and 
A F 2 will be different, causing F, — (F 2 + F,) 
= F. j. Thus a properly polarized voltage will 
appear at the discriminator output. This will 
cause the motor to rotate, compensating R-l 
until E-2 reaches a value sufficient to displace 
F 2 to the point where F x —- (F 2 -f- F 3 ) = F 4 . 
At this point, because of discriminator action, 
the motor will cut off and the speed dial will 
read the corrected speed of the ship. Frequency 
is corrected at the same time. 

The sampling time is not critical and may be 
as long as reverberations suitable for correc¬ 
tion purposes are available. 

The time constant of the delay circuit should 
correspond to the time delay of the maximum 
echo range used. Target-doppler voltage is ap¬ 
plied to a separate, voltage-sensitive oscillator, 
causing its frequency to be displaced from its 
base F 4 by an amount ± A F. This frequency 
F 4 ± AF is then added to F 2 -f F 3 in a ring 
modulator to form the doppler-compensated 
echo frequency. Inasmuch as ship’s speed can¬ 
not change rapidly, previous objections voiced 


against motor control do not apply in this 
method. 

Figure 12 is a schematic of the echo simula¬ 
tor which shows how the sonic speed-control 
system outlined above is incorporated. The 
doppler-corrected echo frequency is applied to 
the input of a keyed amplifier for echo-length 
and echo-delay timing. This is accomplished by 
a system similar to that used in Model I. The 
timed echo is then fed to two bearing-controlled 
keyed amplifiers for BDI phasing and range 
attenuation. 

The latter functions are accomplished by the 
method outlined in Figure 13. The combination 
of the output voltages from northing and east¬ 
ing Variacs X-l and X-2, after traversing the 
Scott transformer T-2, produce in the differ¬ 
ential selsyn primary S-l a 60-c single-phase 
field whose space orientation corresponds to 
the true bearing of the target vessel and whose 
magnitude is a measure of target range. 

R-l and C-l are proportional, so that their 
impedances are equal at 60 c (the supply fre¬ 
quency) and serve in combination with T-3 
to produce a voltage the magnitude of which is 
proportional to target range and independent 
of target bearing. The impedance of the net¬ 
work comprising R-l C-l is so chosen that the 
combination has a negligible effect on the volt¬ 
ages derived from X-l and X-2. 

The differential selsyn secondary S-2 is ori¬ 
ented angularly to correspond to the true bear¬ 
ing of the projector head. When acting in 
combination with the Scott transformer T-4, 
the selsyn produces an alternating voltage at 
point 1 which will be zero with respect to 
ground only when the projector is trained 
directly at the target or directly away from the 
target. The latter condition is an unwanted 
false null which is removed by the action of 
tubes V-2 and/or V-3 when they are served 
with the voltage developed at point 2. The 
voltage developed at point 1 is rectified by V-l 
and V-4 to supply information for bearing and 
BDI operation. The small offset between right 
and left steered lobes of BDI is supplied by 
the center-tapped secondary 3 of T-4. 

As a result of the above action negative 
potentials exist across R-2 and R-3 while the 
projector is trained away from the target. 


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GENERAL DESCRIPTION (MODEL II) 


119 


oc 

PROJECTOR 


WAKE ERROR POT 


PING RELAY 


RANGE SWITCH 


H 


RANGE 

ATTENUATOR 


FIXED 

OSCILLATOR 


ECHO LENGTH 




LEFT 

BEARING 


ECHO 


RIGHT 

BEARING 

AND DELAY TIMER 



KEYED 

AMPLIFIER 


KEYED AMPLIFIER 

-S‘" 

KEYED 

AMPLIFIER 


801 

RECEIVER 




T-l 


jiLl 


T-2 



fM) 


nnnn 


LEFT BEARING 
KEYER 


F,± AF 


RIGHT BEARING 
KEYER 


RING 

MODULATOR 




f+af 

•4— 


21 


RING 

MODULATOR 




MIXER 




ECHO RANGE AND 
BEARING CONTROL 


NORTHINGS 


EASTINGS 


TARGET DOPPLER VOLTAGE- 


TARGET DOPPLER 
OSCILLATOR 


VOLTAGE 

SENSITIVE 

OSCILLATOR 


POTENTIOMETER 

BRIDGE 


DISCRIMINATOR 


REVERSIBLE 

MOTOR 


SPEED INFORMATION - 4 - 
PROJECTOR BEARING 


Figure 12. Electrical schematic for SASAT-B, Model II, echo simulator. 


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120 


SHIPBOARD TRAINERS FOR SOUND OPERATORS AND ATTACK TEAMS 



These voltages are applied to the right and left 
bearing-keyed amplifiers indicated in Figure 
14 and are sufficient in magnitude to cause the 
amplifier tubes to cut off with echo signal ap¬ 
plied. 

As the projector is trained near the true 
bearing of the target, the voltages across R-2 
and R-3 (Figure 13) will approach zero dis¬ 
proportionately, thus removing the cutoff biases 
and allowing the keyed amplifiers (Figure 14) 
to conduct the timed echo. 

The disproportionate values of the applied 
biases (projector slightly off target bearing) 
cause the outputs of the two amplifiers to be 
of different magnitudes. When the projector is 
trained slightly to the right of the target bear¬ 
ing, the output of the right bearing amplifier 
will be greater than that of the left. The op¬ 
posite is true when the projector is trained 
slightly to the left of the target bearing. Both 
amplifier outputs are equal and at a maximum 
when the projector is trained on the target. 

Range attentuation is accomplished by limit¬ 
ing the screen grid current of the keyed ampli¬ 
fiers by the action of V-l and V-2 as depicted 
in Figure 14. 

The timed and doppler-corrected echo is fed 
to a transformer network (Figure 12), which 
phases it properly for application to the BDI 


W T0BD1 PHAS,NG w 



Figure 14. Bearing keyer and range attenuator 
schematic, SASAT-B, Model II. 

receiver. The voltage across winding e is the 
sum of the voltages a and c and represents the 
on-bearing component. Voltage across / is the 


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WEA-l SELSYN ADAPTER UNIT 


121 


differences between voltages h and d, and rep¬ 
resents the right and left component. The 
voltage vector outputs of T-l and T-2 are in 
quadrature because of the insertion of a lag 
line in the primary of T-2. 


96 CONCLUSION 

Shipboard trials of SASAT-B, Model I, suc¬ 
cessfully demonstrated the effectiveness of such 
a device for antisubmarine practice drills. The 
inclusion of the automatic target and scoring 
chart in Model II gave promise of even greater 
effectiveness, in that it supplied more realistic 
simulation of actual attack conditions and an 
accurate method of evaluating a practice run. 
In operations with an actual submarine target, 
misses cannot readily be analyzed. The scoring 
device in Model II is therefore a development 
of distinct value. 



Figure 15. WEA-l selsyn adapter unit (for 
use with SASAT-A). 


WEA-l and WEA-2 Adapters for 
SASAT-A 

WEA-l and WEA-2 adapters for SASAT-A, 
developed by UCDWR, were designed to adapt 
the shipboard antisubmarine attack teacher 
[SASAT-A] for use with the WEA-l and 
WEA-2 sound equipment. These adapters are 
necessary because SASAT-A is designed for 



Figure 16. WEA-2 selsyn adapter unit (for 
use with SASAT-A). 


echo-ranging gear which employs a selsyn bear¬ 
ing repeater and a receiver muting relay not 
used in WEA-l and WEA-2. The WEA-l 
adapter provides a selsyn for gearing with the 
WEA-l projector potentiometer to obtain bear¬ 
ing information for the SASAT; the WEA-2 
adapter selsyn is chain-driven from the shaft 
of the WEA-2 projector hand-training wheel. 
The keying unit for both adapters operates the 
SASAT from voltage pulses developed at the 
time of the outgoing ping. 

9 7 WEA-l SELSYN ADAPTER UNIT 

In WEA-l the rotation of the projector is 
controlled by means of a handwheel geared to a 
potentiometer, which forms one half of a bridge 
circuit for electric control of rotation. The 
other half of the bridge is another potenti¬ 
ometer which is geared to the projector training 
shaft. Any unbalance between these two potenti¬ 
ometers is amplified and operates two relays 
which control the rotation of the motor driving 
the projector shaft. A selsyn mounted on a 
plate with appropriate gears is therefore used 
to supply voltage to the SASAT in accordance 
with the projector bearing. This selsyn unit is 
installed on the chassis behind the remote-con¬ 
trol unit to the right of the crankshaft and 
potentiometer. With the unit secured, the small 
gear (see Figure 15) meshes with the gear 
on the potentiometer. The small gear in turn 
drives the large gear so that the selsyn makes 
one complete revolution for every revolution of 
the projector. 


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SHIPBOARD TRAINERS FOR SOUND OPERATORS AND ATTACK TEAMS 


98 WEA-2 SELSYN ADAPTER UNIT 

In WEA-2 the rotation of the projector is 
controlled manually by means of a flexible 
cable. Figure 16 shows the selsyn and mounting 
plate for this type of gear. This adapter is in¬ 
stalled inside the remote training control unit 
and connected by a chain and sprockets to the 
shaft of the training handwheel. The selsyn 
then makes one complete revolution for every 
revolution of the projector. 


9 9 KEYING UNITS FOR WEA-1 AND WEA-2 

WEA-1 and WEA-2 sound gear use either an 
electronic method of keying or relay-operated 
keying, neither of which is easily accessible. A 
small keying unit, shown in Figure 17, was 
therefore devised to operate from voltage pulses 
generated at the time of the outgoing ping. 
The circuit, illustrated schematically in Figure 
18, employs a 117L7 tube. The diode portion 
T-l is used to rectify the a-c line voltage to 
obtain plate voltage for T-2. C-l filters out the 
ripple and R-4 is a divider across the supply. 
The coil of the relay in SASAT-A is connected 
between terminals 5 and 6 and the pulse ob¬ 
tained from the hand key on the WEA-1 or 
WEA-2 is supplied to terminals 3 and 4. T-2 
is normally biased to cutoff, so that when the 
keying is supplied to the grid the tube draws 
current and the relay is actuated. R-l is the 
grid isolating resistor, R-2 the grid return, and 
R-3 the screen-supply dropping resistor. Switch 
S-l serves to change the bias on T-2 for the 
different types of keying, since WEA-2 keys 
from a minus voltage to ground, and WEA-1 
keys from 0 voltage to a positive voltage. R-5 
and the divided R-4 serve to supply the correct 
bias for these conditions. Because in general 
no ground return is available on the a-c line 
voltage system, one side must be grounded for 
the keying unit to function correctly. A 110- 
volt, 6-watt lamp (S-2) is used to determine 
which side of the line is grounded, if either. 
Therefore, connect the a-c voltage to terminals 
1 and 2. If the lamp glows reverse the a-c con¬ 
nections. If the lamp is not lit, one side of the 
a-c system is grounded and the connections are 


correct. But if the lamp glows brightly with 
either connection it means that there is not a 
solid ground connection in the system. There¬ 
fore, either connection to terminals 1 and 2 



Figure 17. WEA-1 and WEA-2 keying adapter 
unit (for use with SASAT-A). 


should be made and terminal 2 should be con¬ 
nected to ground. 

Since the WEA-1 gear has only one audio 
stage, a 10:1 step-up transformer is placed in 


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KEYING UNITS FOR WEA-1 AND WEA-2 


123 


the audio lead from the SASAT-A to the echo¬ 
ranging gear. This supplies enough voltage for 
the echo to have sufficient volume. Resistor 
R-40 of SASAT-A Model IV need not be used, 



Figure 18. Electrical schematic for WEA-1 and 
WEA-2 keying adapter unit. 


as the transformer gives the isolation neces¬ 
sary when injecting into the audio system of 
WEA-1. In WEA-2 the transformer is not 
needed because two stages of audio amplifica¬ 
tion are used, but R-40 of SASAT-A must be 
increased to 820,000 ohms to give sufficient 
isolation. 

Three versions of the slide rule were con¬ 
structed, each being a simplification and im¬ 
provement of its predecessor. The final model 
is shown assembled in Figure 19 and disas¬ 
sembled in Figure 20. 

The bottom disk, 6 in. in diameter, carries 
the relative bearing scale and two angle T-l 
dials, one for a 10-knot destroyer attacking a 
4-knot submarine, and one for a 15-knot de¬ 
stroyer attacking a 4-knot submarine. In these 
dials the use of course angle is dropped in 
favor of the more familiar concept of target 
angle. 

The bottom disk also carries two diagrams 
for use in calculating the proper angle T-l from 


the original target angle T-0 and the amount 
and direction of the lead. On the angle T-l dials 
the location of the numerical values has been 
rotated through 180 degrees. 



Figure 19. SASAT slide rule. 


SASAT Slide Rule 

The SASAT slide rule is an instrument de¬ 
signed by UCDWR to assist the operator of 
a shipboard antisubmarine attack teacher 
[SASAT 1 -A] in attaining rapid and accurate 
coordination in setting up a practice problem 
with the manually operated SASAT controls. 
However, it was used mainly for analyzing 
maneuvers at the close of practice periods. The 
main components of the instrument are a 
“bottom” disk, a movable disk and a cursor. 
The bottom disk is 6 inches in diameter and 
carries a relative bearing scale. The movable 
disk, U-5 inches in diameter and made of trans¬ 
parent plastic, carries a pair of “cupid’s boiv” 
curves and an “index” line. The cursor, also 
made of transparent plastic, carries range and 
range rate scales and a “pointer” line. The slide 
ride is calibrated to give relative bearings and 
range rates as functions of the distance betiveen 
a submarine and an attacking ship proceeding 
along straight courses at constant speeds. 


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124 


SHIPBOARD TRAINERS FOR SOUND OPERATORS AND ATTACK TEAMS 


Difficulties in determining the results of 
practice antisubmarine attacks led to the de¬ 
velopment of the practice attack meter system. 
In trials under actual training conditions, the 
practice attack meter showed itself to be a 


small explosive charge which is fired by water 
pressure at a depth at which the practicing 
submarine operates. The charges are intended 
to produce, as nearly as possible, uniform ex¬ 
plosive pressures. 



Figure 20. SASAT slide rule, disassembled. 


material improvement over earlier methods of 
evaluating attack runs. It has been suggested 
that, by providing rapidly a quantitative pic¬ 
ture of performance, the meter might also be 
of value in appraisal of developments in attack 
or conning methods and systems. 


910 OPERATING PROCEDURE 

When the surface craft maneuvers into posi¬ 
tion for dropping a depth bomb, it releases a 
special projectile which is part of the practice 
attack meter system. This projectile carries a 


The impulse generated by the exploding 
charge is picked up by a directional hydrophone 
on the bridge of the submarine. In the resulting 
electric impulse, amplified and recorded by a 
meter, two components furnished by quadra¬ 
ture elements in the hydrophone are used to 
determine the bearing of the explosion relative 
to the submarine. Distance of the explosion 
from the submarine is determined by the in¬ 
tensity or amplitude of the impulse reaching 
the hydrophone. These range and bearing de¬ 
terminations are made by associating and in¬ 
terpreting the meter readings on a calculating 
chart. 


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DESCRIPTION OF EQUIPMENT 


125 



Figure 21. Electrical equipment cabinets for 
practice attack meter. 


Practice Attack Meter 

The practice attack meter is a system of de¬ 
vices designed to determine the accuracy of 
surface-vessel crews in carrying out practice 
antisubmarine attacks. The system includes a 
double channel pressure gradient hydrophone, 
amplifying and recording equipment, sub¬ 
caliber depth charges which produce almost uni¬ 
form explosive pressures, a release mechanism 
to discharge the projectiles, and a calculating 
chart for translating the recorder ordinates to 
bearing arid range. In operation, the hydro¬ 
phone, on the bridge of a submarine, picks up 
an impulse from the explosion of the special 
depth charge dropped by a practicing surface 
ship at the center of a hypothetical barrage. The 
resulting electrical pulse is amplified and re¬ 
corded, registering the bearing and the range 
of the point of explosion. The system has a 
range sensitivity suitable for distances up to 
1,000 ft, with an accuracy of reading, indicated 
by standard deviations, of 9 per cent in range 
and 7 degrees in bearing. The system ivas de¬ 
veloped by BTL at the request of Division 6. 


911 DESCRIPTION OF EQUIPMENT 

The system comprises the following five com¬ 
ponents. 

1. A double channel pressure gradient hydro¬ 
phone. 

2. An amplifying and recording system with 
power supply (in three units). 

3. Subcaliber depth charges which produce, 
as nearly as possible, uniform explosive pres¬ 
sures. 

4. A release mechanism to discharge the pro¬ 
jectiles. 

5. A calculating chart for translating the 
recorder ordinates to bearing and range. 

The hydrophone is mounted on the bridge 
structure of the submarine and connected to 
the electric equipment within the submarine. 
The other items are used on the surface ship 
which works with this submarine. 

Projectile 

The projectile consists of a steel tube 
weighted at the head and fitted with a flaring 
wooden tail. Within the tube is mounted the 
firing mechanism. Water pressure acting on a 
copper bellows compresses it and at the proper 
pressure the contact is closed. Current is fur¬ 
nished by a flashlight cell. The electrically fired 
explosive charge is mounted in a jack outside 
the wooden tail. 

It was decided to adopt a design having a 
terminal rate of fall of approximately 6 fps, 
comparable to that of the standard 300-lb depth 
charge. Experience shows that in actual train¬ 
ing operations hypothetical conditions must be 
set up. For routine operations it is not con¬ 
sidered desirable to operate the submarine 
below some rather shallow depth, generally with 
the keel 90 ft below the surface. Yet for pur¬ 
poses of the training problem the submarine is 
assumed to be at some greater depth, generally 
from 100 to 600 ft. Hence some correction will 
be necessary for the short falling time of the 
projectile in training operations, as well as for 
other variables involved. These variables would 
include effects of turbulence, wake, and varia¬ 
tions of depth at which firing occurs. 


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126 


SHIPBOARD TRAINERS FOR SOUND OPERATORS AND ATTACK TEAMS 


The depth at which the explosive charge 
should fire is dictated by several factors. It 
should be sufficiently deep so that the sound 
wave will be unaffected by the wake of the sur¬ 
face vessel. It should be above the wake of the 
submarine although the relative importance of 
the latter is unknown. In order to afford pro¬ 
tection, explosion should occur above the hydro¬ 
phone and periscopes. Accordingly the firing 
mechanism is set to operate at a pressure cor¬ 
responding to a depth of 40 ft. Figure 22 shows, 
to scale, the location of the submarine, surface 
vessel, and charge explosion. 

The explosive used is P.E.T.N., a Hercules 
Powder Company explosive similar to Tetryl. 
The explosive charge as developed consists of a 

O. 259-caliber bronze shell mounted on a coaxial 
plug. The assembly contains an electric igni¬ 
tion fuse, primer, and a charge of 1.35 g of 

P. E.T.N. 

Loading and Release Mechanism 

The projectiles and the explosive charges 
were to be shipped separately, and to arm the 
projectile it was necessary only to insert the 
plug of the charge in the jack of the projectile. 
To insure safety in this operation as well as a 
uniform method of dropping the projectile, a 
combination loading and firing assembly was 
designed which provides a safety loading 
chamber and means for electrically releasing 
the projectiles overside. A preliminary design 
was also worked out for a magazine-type re¬ 
lease in which, after loading in the safety 
chamber, the projectiles would be stacked in a 
magazine ready to be released one at a time as 
required. 

Hydrophone 

In selecting a hydrophone design which would 
be suitable for use in this system it was neces¬ 
sary to satisfy several requirements: 

1. Approximation to true cosine directivity 
pattern. 

2. Frequency range. 

3. Ruggedness. 

4. Response. 

The entire operation of the system depends 
on the directivity pattern of the hydrophone, 
which should be two cosine patterns with 


their principal acoustic axes at right angles. 

The practice attack meter must function 
positively on the explosive pulse originating 
anywhere within the intended range and at the 
same time avoid false operation on interfering 
disturbances. There are two principal sources 
of such interference. At frequencies above 



Figure 22. Location of submarine, surface 
vessel, and charge explosion. 


16,000 c, normal operation of QC systems must 
be expected to produce high-intensity disturb¬ 
ances. In the low-frequency region, water 
noise, including turbulence around the hydro¬ 
phone, and ship noise predominate. To exclude 
these disturbances a band-pass filter is em¬ 
ployed, the bandwidth ranging from 500 to 
16,000 c. This bandwidth is adequate to retain 
the asymmetrical form of the pulse sufficiently 
undistorted to avoid ambiguity. Margin against 
false operation is assured by choice of a suffi¬ 
ciently powerful explosive charge combined 
with a relatively low response in the hydro¬ 
phone, which covers most of this range with 
reasonable uniformity. Inasmuch as the type 
of rectifier circuit adopted has in effect a re¬ 
sponse which falls off 6 db per octave, the lower 
part of the hydrophone frequency range is of 
principal importance. 

Without impairing its acoustical perform¬ 
ance, the hydrophone must be sufficiently 
rugged to withstand continual operation on 
board the submarine. This is a severe require¬ 
ment when it is considered that it must with¬ 
stand not only motion through the water but 
also the effects of breaking waves during div¬ 
ing and surfacing. 

The requirement of response is lenient be¬ 
cause of the high acoustic pressure developed 
by the exploding charge. In the frequency band 
below 50,000 c the pressure 16 ft away is 


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PRINCIPLE OF OPERATION 


127 


7 X 10° dynes per square centimeter for the 
1.35 g P.E.T.N. charge. 

The first hydrophone, which was unsatisfac¬ 
tory, consisted of two standard pressure 
gradient instruments in a water-filled Lucite 
housing. The next model 2 included two inertia 
operated assemblies within a single spherical 
shell. The units used are the same as those in 
the bone conduction receiver of the Orthotech- 
nic audiphone. 3 The chief advantage of the in¬ 
ertia type of instrument is that it eliminates 
the necessity of diaphragms or other means of 
applying pressures from the acoustic wave to 
the active elements. The shell is made of alumi¬ 
num, 2Vic in. in diameter, with a wall thickness 
of y 1G in. It resonates at 13,000 c, which is the 
upper limit of usefulness of the hydrophone. 4 - 5 
The lower limit is 600 c. 

During experiments it was found that mov¬ 
ing the hydrophone through the water at cer¬ 
tain speeds would induce transverse vibrations 
of the head of the hydrophone with respect to 
the stand. The remedy was to support the 
sphere about its equator with a ring, which in 
turn is attached to the support with a cage-like 
structure (see Figure 23). 

The entire support with the hydrophone in 
place has a transverse resonant frequency of 
the order of 10 c, thus forming a low-pass filter 
which protects the hydrophone from ship vi¬ 
brations. 

Electrical System 

Three cabinets contain the electrical equip¬ 
ment. In Figure 21, the top cabinet at the right 
holds the recorder. The cabinet below it has the 
control circuit at the top below which are the A 
and B amplifier and detector panels. (A and B 
refer to the two hydrophone units.) The left 
cabinet contains the regulated power supply at 
the top and the converter circuit below. 


PRINCIPLE OF OPERATION 
Circuit Description 

The operation of the electrical system is ex¬ 
plained with reference to the simplified circuit 
diagram, Figure 24. The pulse from an explod¬ 
ing charge is received at the hydrophone, and 



Figure 23. Hydrophone on stand. 


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128 


SHIPBOARD TRAINERS FOR SOUND OPERATORS AND ATTACK TEAMS 


the outputs of the two elements A and B are 
fed through separate attenuators for adjust¬ 
ment of range and for balance. Since the per¬ 
formance of the two channels is similar, the 
operation of the A channel only will be con¬ 
sidered. 


Outputs from both rectifiers are amplified at 
6 and 7 and fed through the 150-qsec delay net¬ 
work to operate the relay. This initiates a num¬ 
ber of operations. First contact 1 is opened, 
disconnecting the hydrophone from the recti¬ 
fiers. This is important, since any pulse reaching 




CIRCUIT NORMALLY 
CLOSED, OPENED 
BY OPERATION OF 
CONTROL CIRCUIT 


CIRCUIT NORMALLY 
OPEN,CLOSED BY 
OPERATION OF 
CONTROL CIRCUIT 


Figure 24. Practice attack meter—simplified circuit diagram. 


The pulse is amplified and fed to rectifiers 4 
and 5. If the explosive pulse is received on the 
forward (positive) lobe of the A hydrophone 
element, the electric pulse will be positive and 
will be rectified by rectifier 4. The output of 
this rectifier acts immediately to open contact 
3, so that the succeeding negative portion of 
the signal will not pass to rectifier 5. The output 
of rectifier 4 is amplified and charges con¬ 
denser 10 to a voltage proportional to the mag¬ 
nitude of the pulse. 

Had the pulse been received on the rear lobe 
of element A the electric pulse would have been 
negative. It would have been passed by rectifier 
5, disconnecting rectifier 4 at contact 2, and 
condenser 11 would have received the charge. 


the hydrophone more than 150 qsec (the time 
taken for sound to travel 8.5 in. in water) later 
than the initial pulse will be ignored. Thus 
echoes of the explosion from the water surface 
or from parts of the submarine cannot intro¬ 
duce errors in the readings. At the same time 
the relay actuates a clutch in the recorder which 
starts the paper moving and starts a motor- 
driven sequence switch which takes 8 sec to 
make a complete revolution. Initially the record¬ 
ing meter is connected to condensers 10 and 11 
through their isolation amplifiers and reads the 
voltage to which one of these is charged, a posi¬ 
tive reading if 10 is charged, negative if 11 is 
charged. After 2 sec the meter is disconnected 
at contact 14 and connected to the amplifiers 


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PRINCIPLE OF OPERATION 


129 



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TO“b"BAND-PASS TO-“b“ TO h B“ TO V to"b" 

FILTER GAS TUBE OUTPUT V RELAY AND IIO V “E" RELAY AND 110 V 

Figure 25. Practice attack meter—system schematic. 





























































































































































































































130 


SHIPBOARD TRAINERS FOR SOUND OPERATORS AND ATTACK TEAMS 


following condensers 8 and 9. These were 
charged from the B hydrophone element in a 
fashion similar to that described for A. After 
being connected to the B channel for 2 sec the 
meter is disconnected and the condensers in 
both channels are discharged by the closing of 
contacts 12, 13, 16, and 17 for 2 sec. After 2 
more sec the sequence switch opens contact 15 


and is ready to receive another pulse whenever 
it may arrive (see Figure 25 for system sche¬ 
matic). A detailed description of the electric 
circuit will be found in the bibliography. 0 

Calibration 

Overall calibration of the system is done by 
means of test charges located at a known dis- 



momentarily, releasing the relay, and the cycle tance on the submarine. Tables have been pre- 
is complete. The equipment is in the stand-by pared showing expected readings for various 
condition with the paper in the recorder stopped switch settings. After calibration the system is 


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TESTS OF THE SYSTEM 


131 


ready for use, the only precaution being that 
the sensitivity switch should be set for the range 
desired. The maximum range, 200 to 1,000 ft, 
is obtained by the 0-db setting. Each 6-db re¬ 
duction in the sensitivity divides the range 
figures by 2, the calculating chart having been 
plotted on the basis of 12-db reduction, or 50 
to 250 ft. Since the cam cycle is 8 sec, for two 
explosions closer together than about 8 sec 
only the first will be recorded. 


CALCULATING CHART 


deflection scale is shown down to only 10 as a 
compromise between size and accuracy of the 
chart and because inherent inaccuracies cause 
greater percentage errors at the lower scale 
readings. The minimum distance that can be 
read from the chart is 35.5 to 50 ft, whereas 
the maximum distance is 262 to 372 ft, depend¬ 
ing on the bearing. Where only one reading is 
below 10 the location can be estimated by the 
chart, since the low reading does not greatly 
affect the distance. For both readings below 10 
the formulas given can be used. 


It has been shown that the response of a unit 
of the hydrophone to a charge fired on its axis 
is inversely proportional to the distance. For a 
charge not on either axis, and with certain as¬ 
sumptions, range and bearing may be calcu¬ 
lated as follows: 


R = 


5,200 


V(D a + 4) 2 + (D b + 4) 2 

- 45 ° + tan ~‘ Z5JT7 


where R is the range in feet, 

D a and D B are the meter deflections, 

0 is the bearing in degrees with respect to 
the ship, assuming clockwise angles as 
positive. 


To eliminate computation except in a few 
cases, the calculating chart shown in Figure 26 
has been prepared. A positioning pin obtrudes 
through a hole at the center of the chart and a 
transparent cross-shaped slider is supplied with 
a slot which slides along the pin. Two crossed 
scales labeled A- (-, A — and B-\-, B— corre¬ 
spond to the meter deflections. The drawing 
shows the position of the slider for a recorder 
reading of A- f- = 40 and B — = 15. At the 
center of the slider a hole permits drawing a 
small circle for the location of the explosion. 
From the circular outside scale this is seen to be 
at a bearing of 292 degrees. The range from 
the hydrophone, located at the pin, read on the 
slider scale where it crosses the circular out¬ 
side scale, is 109 ft. Contour lines drawn around 
the hull show that the explosion was about 90 ft 
from the nearest point on the hull. The meter 


9.14 TESTS OF THE SYSTEM 7 

Trials were made to determine the perform¬ 
ance of the practice attack meter and to dis¬ 
cover the explosive effects of various charges. 
The results of some tests were erratic because 
of the influence of wake. This situation will not 
be encountered in actual practice where ex¬ 
plosion will take place 40 ft below the surface. 
Surface reflections, due mainly to the longer 
delay of 500 psec in the operation of the dis¬ 
abling circuits of the detectors, also contributed 
to observed discrepancies. 

Calibration tests were made to determine the 
accuracy of the system. Results show that the 
true system error distribution has a standard 
deviation between 7 and 9 per cent for range. 
For bearing the deviation is between 3.5 and 7 
degrees. Some factors causing variations be¬ 
tween tests are the trajectories and firing times 
of the projectiles, the influence of wakes and 
other transmission irregularities in the me¬ 
dium. Among the more important differences 
in the overall calibration is the technique of 
calibration itself. Assumptions are involved 
such as maintenance, throughout a run, of 
known and straight courses at strictly uniform 
speeds for both surface vessel and submarine. 
These assumptions are not, of course, strictly 
valid. Furthermore, the determination of the 
theoretically correct firing points involves a 
measure of judgment and approximation. The 
errors introduced thereby are unquestionably 
more critical for bearing than for range and 
may well be comparable in magnitude to the 
true errors of the system itself. 


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SHIPBOARD TRAINERS FOR SOUND OPERATORS AND ATTACK TEAMS 


9 15 RECOMMENDATIONS AND 
CONCLUSIONS 

Recommended Mechanical Changes. 

1. Because the various dials on the electric 
equipment used to adjust different parts of the 
circuit were too easily disturbed from their 
proper setting, it seems desirable to move those 
which are infrequently used, such as the hydro¬ 
phone sensitivity adjustments, inside the panel, 
and to provide the others with screwdriver 
slots rather than knobs. 

2. The visual meter wired in series with the 
recording meter was seldom if ever used and 
should be removed. 

3. The electrical calibrating circuit should be 
improved to eliminate false calibration read¬ 
ings caused by erratic functioning of the cali¬ 
brating switch. 

4. The projectile release mechanism, which 
was far from foolproof, might be replaced by a 
magazine type of device. 

5. A more comprehensive plotting board, 
with all horizontal distance scales in yards to 
conform to Navy practice, seems desirable. 

Training Problems. In the application of the 
practice attack meter to training problems, the 


two important facts given must be considered. 

1. The information developed in practice at¬ 
tacks should be obtained quickly and in such 
form that it will be clear to the trainee. 

2. A visual representation is necessary. This 
would show the actual relation between the 
point of explosion and the location of the target 
submarine. 

Conclusions. Trial of the practice attack 
meter under actual training conditions indi¬ 
cated that it was practicable for the purpose 
intended and was a material improvement over 
methods then in use to determine the results 
of practice attacks. 

It is directly applicable to other types of 
training attack, such as by the ahead-thrown 
projectile. Equipment of the subcaliber projec¬ 
tile used in this system with a charge fired at 
the proper depth would permit using a single 
projectile representing the center of the bar¬ 
rage. It would give positive indication of accu¬ 
racy of aim even though a direct hit is not 
scored. 

The meter may also be of value in appraisal 
of new and experimental attack or conning 
methods and systems by providing rapidly a 
quantitative picture of performance. 


RESTRICTED 



Chapter 10 

PRACTICE TARGET EQUIPMENT 


B ecause of the extravagance of using sub¬ 
marines in echo-ranging training maneu¬ 
vers, various types of practice targets were 
developed as substitutes. An important econ¬ 
omy was thus achieved and the training pro¬ 
gram was accelerated. 

Practice targets, consisting essentially of 
echo repeaters, are mounted on stationary 
buoys, on the keels of target vessels, or are 
towed underwater, so that sonar operators can 
ping at them and receive echoes closely simu¬ 
lating those returned by a submarine, as well 
as genuine reverberation. Since real reverbera¬ 
tion and echoes are much more difficult to dis¬ 
tinguish than artificially generated reverbera¬ 
tion and echoes, practice targets provide a more 
advanced type of training than shore-based at¬ 
tack teachers. They do not, however, provide 
wake echoes, which sonarmen must learn to 
distinguish from the true submarine echo. 
Towed targets may return a very faint wake 
echo, but nothing comparable to that of a sub¬ 
marine wake. It is therefore advisable that some 
part of echo-ranging maneuvers include prac¬ 
tice with an actual submarine targets 

Although the series of targets designed for 
training purposes were of different types, they 
were all based on the same general principles. 
In the summary which follows, the general prin¬ 
ciples are outlined first, followed by a descrip¬ 
tion of the individual targets, BR-1, RR-1, 
KR-1, SR-2, and SR-5, developed at the Uni¬ 
versity of California Division of War Research 
laboratory [UCDWR] at San Diego. Echo re¬ 
peaters developed at the Harvard Underwater 
Sound Laboratory [HUSL] were used only for 
calibration and testing. In the event of further 
development work, however, they could also be 
applied in the training field. The Harvard echo 
repeaters are described in Division 6, Vol¬ 
ume 18, Chapter 6. b 

a To mark the position of a submarine when sub¬ 
merged during testing and training exercises, a marker 
buoy was developed to be towed by the submarine. To 
extend its range of visibility, a smoke signal was later 
added to this marker buoy. These devices are described 
in Division 6, Volume 18, Chapter 11. 

b Practice targets and other training devices used 
with magnetic airborne detection equipment are dis¬ 
cussed in Division 6, Volume 5, Chapter 7. 


101 GENERAL PRINCIPLES 

When an underwater sound beam from an 
attacking ship strikes a submarine, part of the 
energy from that sound beam is reflected and 
may be picked up by the sound gear of the at¬ 
tacking ship. A target that is to substitute for a 
submarine must simulate its reflection in in¬ 
tensity, directional effects, and frequency 
changes. 

In order to meet these requirements, the 
practice target must have a hydrophone (re¬ 
ceiver transducer) with uniform response 
about its normal axis, an amplifier to raise the 
level of the signal received, and a projector 
(transmitter transducer) with uniform re¬ 
sponse about its normal axis. Ideally the trans¬ 
ducers should be so designed and mounted that 
their response drops to zero when the attacking 
vessel approaches a position directly over the 
target. The mechanical design of the target 
should also incorporate the type of streamlining 
and trim necessary to simulate, when towed, the 
motion of a submarine. 


102 TRANSDUCERS FOR PRACTICE 
TARGETS 

Both hydrophone and projector transducers 
used in the San Diego practice targets consist of 
45-degree x-cut Rochelle salt crystal stacks. The 
hydrophone picks up energy from the ping sent 
out by the sonar practice team and converts it 
into an electric signal. This signal is amplified, 
converted back into sound energy at the pro¬ 
jector, and re-radiated into the water, thus pro¬ 
ducing a strong artificial echo. The artificial 
echo has many of the fundamental character¬ 
istics of a true submarine echo. For example, 
its loudness is proportional to the loudness of 
the transmitted signal. In the case of towed 
targets, the doppler effect is also present, since 
the frequency of the repeated echo is altered 
in accordance with the motion of the target 
just as an actual submarine echo would be. 

These effects are obtained, however, only if 
the water temperature remains in the neigh- 


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133 



134 


PRACTICE TARGET EQUIPMENT 


borhood of 75 F. Above or below this tempera¬ 
ture, x-cut Rochelle salt crystals suffer a 
marked drop in sensitivity. In the Atlantic, 
which has wide temperature variations, the 


Figure 1. BD-1 transducer. 

San Diego practice targets were not so effective 
as in the Pacific. Because of this serious limita¬ 
tion in the sensitivity of Rochelle salt crystals, 
the use of ADP crystals in practice targets 
might well be explored. 

Acoustical coupling between the projector 
and the hydrophone, if pronounced, would cause 
the repeater to “howl.” To prevent this, the 
transducers are carefully insulated from the 
metal parts adjacent to them, and are mounted 
as far apart as other considerations permit. In 
addition, they are so oriented that each is in 
the low-sensitivity area of the other’s direc¬ 
tivity pattern. 

Transducer Directivity Patterns 

The construction of the crystal stacks leads 
to directivity patterns which are fairly uniform 
opposite the transducer face but which begin 
to shrink approximately 12 degrees from the 
plane through the face. (The transducer face, 
which is the free surface of the crystal stack, 
is usually indicated on the outside of the hous¬ 
ing by a name plate.) Since the transducers are 
generally mounted with faces normal to the 


beam of the towing vessel, the drop in sensi¬ 
tivity means that the effective target strength 
decreases when the attacking vessel is pinging 
from an angle of 12 degrees or less to either 
side of the target’s bow or stern. These direc¬ 
tional characteristics correspond closely to the 
actual dependence of a submarine’s target 
strength on aspect angle. The regions of low 
sensitivity, being adjacent to one another be¬ 
cause the transducers are mounted in the same 
plane, not only minimize acoustical coupling 
but also serve to reduce undesirable pickup of 
the towing vessel’s screw noise. 

The two chief types of transducer used in 
the sonar practice target are the BD-1, illus¬ 
trated in Figure 1, and the CD-I, illustrated 
in Figure 2. The frequency response and di¬ 
rectivity patterns for these two types of trans¬ 
ducer are shown in Figure 3. 

In the BD-1, when it acts as a projector, the 
drop in sensitivity mentioned above is pro¬ 
nounced. The box-like metal housing produces 
a blind spot of 30- to 40-db attenuation along 
the 90- to 270-degree axis, as shown in Figure 
3A. As a receiver, however, the BD-1 trans¬ 
ducer directivity pattern does not show this 



Figure 2. CD-I transducer. 


blind area along the 90- to 270-degree axis, but 
does have two lesser blind areas 10 to 12 de¬ 
grees on either side of that axis (see Figure 
3A). 




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TRANSDUCERS FOR PRACTICE TARGETS 


135 


The CD-I type of transducer, on the other 
hand, has a directivity pattern, both as trans¬ 
mitter and as receiver, in which the weakened 


The BD-1 Transducer. BD-1 transducers 
serve as hydrophone and projector in both the 
RR-1 raft-suspended and the KR-1 keel- 


330* 


300° 


270° 


240° 



330° 


30 * 


60* 300° 


90* 270* 


120* 240‘ 


90 


> 70 


- 50 


210° 

l( 

)0“ 150° 








A 






(100 MA) CDI - 

/ 


/ 

j 

j 

\ 







V 

v 


S' 

X 







/ 

/ 

/ 

* 

r 




(10 MA) BD 1—, 

/ 

/ 





C 




r 








90* 


210 “ 


180° 


150* 



1000 


10,000 

FREQUENCY IN C 


1000 


10,000 

FREQUENCY IN C 


100,000 


Figure 3. Directivity and response curves of BD-1 and CD-I transducers. 


sensitivity areas are much less pronounced and 
occur at about 25° to 30° angles from the plane 
of the crystal faces (see Figure 3B). These 
characteristics are common also to the CG-1 
and CJ-1 transducers. 


mounted targets. Each transducer consists of 
a double bank of 24 Rochelle salt crystals, each 
1x14/2 x% in., insulated by corprene pads and 
spacers and immersed in vapor-free castor oil. 
When installed in the target, the two banks of 


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136 


PRACTICE TARGET EQUIPMENT 


crystals in the hydrophone are connected in 
series so that they are in phase. Those in the 
projector are connected in parallel, 180 degrees 
out of phase. Operating the transducers in this 
way reduces acoustical coupling to a minimum, 
permitting maximum gain settings for the 
amplifier. 

CD-I, CG-1, and CJ-1 Transducers. CD-I, 
CG-1, and CJ-1 transducers are used as hydro¬ 
phones and projectors in the SR-2, SR-5, and 
BR-1 practice targets. They are all alike, ex¬ 
cept that CG-1 has mounting brackets of a 
different size, and CJ-1, which superseded CD-I, 


supply is needed with an amplifier suitable for 
use with this power. 

Because the sensitivity of the transducer 
crystals varies with temperature, dropping off 
noticeably above or below 75 F, the amplifiers 
are designed to have approximately twice the 
gain required for satisfactory operation at 70 F. 

Table 1 gives the specifications for the vari¬ 
ous amplifiers used with sonar practice targets, 
which are all similar in layout and operation. 
Figure 4 is a schematic diagram of a typical 
target amplifier, the S3-AB. 

The frequencies used by the attacking ships 


has a 1/4,-in. tire-stock 

rubber sleeve. These 

fall in the 

range 16 

to 26 kc. The target re- 


Table 1. 

Comparison of 

amplifier specifications. 




Amplifiers for use with A/S practice targets 




SI 

Sl-AB 

S2-AB 

S3-AB 

U2-AB* 

S5-AB 

Frequency range (kc) 

17-26 

16-26 

16-26 

16-26 

16-26 

16-26 

Input impedance (ohms) 

100 

125 

125 

125 

125 

125 

Output impedance (ohms) 

100 

125 

125 

125 

125 

125 

Overall gain (db) 

90 

108 

114 

114 

116 

114 

Total watts (125-ohm load) 

6 @ 100 

9.2 

8.7 

8.7 

8.7 

8.7 


ohms 






Watts less than 5% dist. 


4.0 

4.0 

4.0 

4.0 

4.0 

B volts (full load) 

290 

275 

295 

295 

280 

295 

Type of B power supply 

Mallory 

Mallory 

Mallory 

Mallory 

A. T. & R. Co. 

Mallory 


VP552 

VP552 

VP552 

VP552 

Type 12RSA 

VP552 


Vibrapack 

Vibrapack 

Vibrapack 

Vibrapack 

Inverter 

Vibrapack 

Total storage battery drain (am 

p) 9 

5.8 

6.5 

6.5 

13 

7 


@ 6 v 

@ 6 v 

@ 6 v 

@ 6 v 

@ 12 v 

@ 6 v 

Used on A/S PT’s 

RR-1 

KR-1 

RR-1 

BR-1 

SR-2 

SR-5 


KR-1 

RR-1 

KR-1 






BR-1 






* AC voltage at U2-AB control cabinet, 115 to 117. 


transducers make use of a single stack of 26 
Rochelle salt crystals, each *4x%xli/2 in., con¬ 
nected electrically by strips of German silver 
foil and immersed in vapor-free castor oil. The 
perforated metal cylinder which serves as a 
protective housing in this model (see Figure 2) 
has about 50 per cent open area and offers 
good acoustical transparency between crystal 
faces and the cylindrical rubber outer casing. 


10 - 3 AMPLIFIERS FOR PRACTICE 
TARGETS 

Since practice targets are generally operated 
from small boats, buoys, or rafts lacking an 
a-c power source, a battery-operated power 


ceiver picks up any signal in this range and 
feeds it into the amplifier input. In operation, 
heterogeneous signals may reach the target 
receiver as the result of reflections, screw noise, 
and reverberation. If the signal that is re¬ 
emitted is to represent the echo from a sub¬ 
marine, it is necessary to eliminate these 
unwanted frequencies before amplification 
takes place. This is accomplished by a band¬ 
pass filter that couple stage 1 and 2 in the 
amplifier. 

Figure 5 shows the band-pass filter, which 
consists of two inductively coupled resonant 
circuits. This filter has been adjusted to give 
the pass band shown in the figure as the overall 
amplifier frequency response. On either side of 
this pass band, signals are attenuated to such 


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AMPLIFIERS FOR PRACTICE TARGETS 


137 



RESTRICTED 


Figure 4. Schematic diagram of S3-AB target amplifier 










































































































































































































138 


PRACTICE TARGET EQUIPMENT 


an extent that they do not appreciably affect 
the second stage of the amplifier. 

The filter output is amplified, as shown in the 
schematic diagram (Figure 4), and applied 
to the power output tubes. These in turn are 
coupled to the projector transducer which pro¬ 
jects the signal as a simulated submarine echo. 

Since the band-pass filter provides a flat 
acoustical operating region from 16 to 26 kc, 
it can accommodate simultaneous signals from 



10 20 3 0 40 

FREQUENCY IN KC 


B + O- 


O 


S o J 

s § 5 

* 2-1 

> 

. O 

o 2 < 

o 1 

o 

> o 


Figure 5. Band-pass filter for S3-AB amplifier. 


several sonar equipments operating at different 
frequencies within the band. Provided they 
operate at frequencies which do not overlap 
and cause mutual interference, several ships 
may ping at one time at the same target. 

The amplifier and power supply are mounted 
near the power source in all the targets except 
the SR-2. With the same exception, all have 
transducers fed through not more than 50 ft 
of cable. Each of the amplifiers, except the 
U2-AB in the SR-2, operates from a 6-volt stor¬ 
age battery connected to a Mallory Vibrapack, 
which develops 275 to 300 volts at 100 ma for 
the amplifier plate supply. In the SR-2 target, 
which is designed for towing on cables as long 
as 1,200 ft, the amplifiers and power supply are 
housed in the target body. To avoid too fre¬ 
quent opening of the target, which would be 


necessary if batteries were installed in it, an 
a-c operated amplifier was designed for this 
model. An inverter mounted in the towing 
vessel is used to develop the alternating current, 
which is fed to the power supply through the 
towing cable. 

The amplifiers provided for the sonar prac¬ 
tice targets appear to have given satisfactory 
service, but any future research or develop¬ 
ment on such targets should take into consider¬ 
ation the later amplifiers built for the 6- and 
10-in. NAD beacons, discussed in Division 6, 
Volume 19. 

Brief summaries of the various practice tar¬ 
get models developed for use in sonar training 
exercises follow. Operational data may be ob¬ 
tained from the instruction manual covering 
the individual type of target (see bibliogra¬ 
phy). 



Figure 6. Practice target, model BR-1. 


RESTRICTED 




























AMPLIFIERS FOR PRACTICE TARGETS 


139 


Practice Target Model BR-1 

The model BR-1 practice target, developed 
by UCDWR at the request of the West Coast 
Sound School, is a stationary buoy-supported 
echo repeater for use in training sonar opera¬ 
tors. Since this target does not provide doppler 
or range rate, it is used chiefly to drill indi¬ 
vidual sonarmen in the recognition of reverbera¬ 
tion and echo signals. The essential components 
of the device are a hydrophone, a transmitting 
projector, an amplifier and a power supply. The 
hydrophone and projector are identical crystal 
transducers (type CG-1 or CJ-1). They are 
suspended by means of a manila rope at a depth 
of 27 ft from the bottom of a steel buoy, which 
houses the amplifier (model Sl-AB or S3-AB), 
the power source and the control equipment. A 
glass covered panel above the amplifier carries 
the off-on switch, the gain control, a battery 
voltage meter, and a signal indicator meter. A 
glass window in the buoy top permits the opera¬ 
tor to observe the meters, and control handles, 
extending up from the panel to valves in the 
buoy top, enable him to make necessary adjust¬ 
ments. A special jellied electrolyte is used in 
the battery power supply; the batteries, housed 
in the bottom of the buoy, help to provide 
proper trim. 

The buoy is made from a seamless steel bilge 
barrel to which suitable fittings are attached. 
In the bottom of the barrel stuffing boxes pro¬ 
vide entrance for the transducer cables and a 
mounting bracket supports the transducer as¬ 
sembly. Lifting rings make handling easy, and 
legs attached to the bottom of the buoy make 
it possible to stand the buoy on deck or dock 
without damaging the equipment. The amplifier 
is mounted inside the buoy near the top with a 
control panel above it. 

Two 6-volt batteries are installed in the 
bottom of the buoy. Since the BR-1 is subject 
to considerable rolling and tipping, it is neces¬ 
sary to use batteries with jellied electrolyte 
which require special care in charging. 1 - 2 After 
this buoy had seen service, it was also found 
necessary to add a gas-venting system, because 
storage batteries of the type used in the BR-1 
generate hydrogen gas at all times, whether 


standing idle or under load, thus giving rise 
to a danger of explosion. 3 A further modifica¬ 
tion in later models was the addition of stronger 
transducer supports. 34 

Two types of amplifier have been used with 
this target, the Sl-AB and the S3-AB. The 
S3-AB, shown in the schematic diagram in 
Figure 4, is similar in operation to the Sl-AB 
but has a somewhat higher gain and a higher 
B power supply voltage at the output terminal 
block (see Table 1). Detailed circuit analyses 
will be found in the appropriate instruction 
manuals. 14 - 24 



Figure 7. Practice target, model RR-1. 


Practice Target Model RR-1 

The model RR-1 practice target developed by 
TJCDWR is a raft-type towed underwater echo 
repeater used in sonar maneuvers. Two BD-1 
type transducers are suspended at a depth of 6 
ft from a wooden raft or spar and spaced 10 
ft apart to prevent acoustical coupling. A band¬ 
pass amplifier (Si, Sl-AB, or S2-AB) and the 
power source (a 6-volt storage battery) are 
carried aboard the boat which tows the raft. 
The apparatus is designed to return echoes in 
the range of frequencies from 17 to 26 kc. By 
picking up and transmitting the screw noise of 
the towing vessel, this gear will also roughly 
simulate submarine propeller sounds. 

The method of housing the transducers is 
illustrated in Figure 8. The transducer is in- 


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140 


PRACTICE TARGET EQUIPMENT 


serted into the streamline socket from below 
and held in place by a bolted cover plate. A 
lining of Vs-in. corprene insulates the trans¬ 
ducer acoustically from the metal holder. Elec¬ 
tric cable connections extend from the trans¬ 
ducers through the supporting pipes, through 
a groove, and under a cleat on the top side of 
the wooden float, and thence to the towing 
boat. A free length of 35 ft of cable is provided 
between this cleat and the terminating ampli¬ 
fier connectors. 



Figure 8. Streamline transducer housing in tar¬ 
get model RR-1. 


Table 1 gives the gain and power output 
ratings of the three types of amplifiers suit¬ 
able for use with this model. 

With the RR-1 practice target, it is also 
possible to simulate roughly the screw noise 
of a submarine. The propeller noise of the tow¬ 
ing craft is picked up and projected with the 
echo. This is accomplished by connecting the 
two transducers so that the forward one is the 
hydrophone. The raft is towed further forward 
than usual and at one side of the stern of the 
towing craft so that the hydrophone is nearly 
abeam of the propeller. Since the towing boat 
is moving slowly, its propeller speed is roughly 
that of a submarine. Towing the target abeam 
of the propeller places the latter opposite a 
lobe of the hydrophone directivity pattern, 
rather than in a “dead” area. 



Figure 9. Practice target, model KR-1 (only 
one transducer installation shown). 

Practice Target Model KR-1 

The model KR-1 practice target is a keel- 
mounted echo-repeater developed by UCDWR 
for use in sonar team training maneuvers. It 
consists of two model BD-1 Rochelle salt crystal 
transducers (a hydrophone and a projector) 
coupled to a 16- to 26-kc band-pass amplifier 
(model Sl-AB) ivith a maximum voltage gain 
of 106 db. The hydrophone and the projector 
are attached to the keel of the target boat near 
the bow and stern respectively. The transducer 
cables are carried into the ship through water¬ 
tight stuffiing boxes in the hull. The amplifier 
and power supply can be located at any con¬ 
venient point on board the target boat. When 
an underwater sound “ping” from the prac¬ 
tice ship strikes the hydrophone, a voltage ap¬ 
pears across its output terminals. This voltage 
is amplified and then fed into the projector, 
which transmits its output to the water as a 
simulated echo. 

10 4 COMPARATIVE EVALUATION OF 
THE KR-1 AND RR-1 TARGETS 

Although considerably more efficient in op¬ 
eration than the RR-1, the KR-1 is limited in 
application. It requires a custom-built mechani¬ 
cal structure to mount the transducers on the 


RESTRICTED 





























COMPARATIVE EVALUATION OF THE KR-1 AND RR-1 TARGETS 


141 


keel of the target boat, as the keel dimensions 
of different boats vary greatly. Furthermore, 
the target boat must be put in dry dock in 
order to mount the transducers and to install 
the necessary watertight stuffing boxes that 
carry the transducer cables through the ship’s 
hull. The KR-1 thus involves the use of a par¬ 
ticular vessel; the RR-1 can be used with any 
available towing craft. In order to match the 
transducer depth of the RR-1, the KR-1 must be 
mounted on a vessel of at least 6-ft draft. 

In general, however, once the installation is 
completed, the KR-1 is superior to the RR-1 
for sound training purposes. Since the trans¬ 
ducers are permanently attached to the keel of 
the target vessel, there is no towing or handling 
problem, and no danger of entangling the trans¬ 
ducer cables in the propeller of the towing 
vessel, as sometimes happens with the RR-1. 
The spacing between the transducers is limited 
only by the keel length of the target vessel, 
which usually allows a greater transducer 
separation than the 10-ft spacing used on the 
RR-1. This greater separation reduces acous¬ 
tical coupling and so permits use of higher 
amplifier gain levels without danger of feed¬ 
back. 

Moreover, training can be carried on in any 
type of weather in which the practice ship can 
operate. This is not true of operation with the 
RR-1, which is a difficult unit to handle in 
heavy seas. The target ship equipped with KR-1 
can proceed to the operating area at any de¬ 
sired speed. The RR-1, on the other hand, is a 
low-speed towing unit, and considerable time 
is lost if any appreciable distance must be cov¬ 
ered to reach the operating area. 



Practice Target Model SR-2 

The model SR-2 'practice target, developed by 
UCDWR, is a U-ft long towed underwater echo 
repeater used in sonar maneuvers. The type 
TJ2-AB amplifier and power supply are housed 
in the body of the target and the two trans¬ 
ducers (CD-I, CG-1, or CJ-1) are mounted in 
the vertical tail fins; a remote control cabinet 
is carried aboard the towing vessel. The target 
can be toived on as much as 1,200 ft of cable at 
speeds which permit simulated attack runs in 
deep water. 

The Model SR-2 practice target is shown 
with its accessory equipment in Figure 10. 
Welded to the iron body of the target, which is 
14 in. in diameter and 4 ft long, is a conical 
tail section 20^ in. long, with four radial fins. 
The towing cable is secured to the center of the 
target head through a flexible, watertight, 
neoprene nose. Proper trim is obtained by plac¬ 
ing ballast in the forward end of the body and 
on the lower vertical fin. Fully assembled, the 
target weighs about 340 lb and has a small 
positive buoyancy above that required to sup¬ 
port the tow cable. 

The transducers used in the SR-2 practice 
target are the CD-I, CG-1, or CJ-1, described 
earlier in this chapter. Figure 11 shows how 
the transducers are attached to the vertical fins 
of the target. To prevent acoustical feedback 
through the metal, the metal cases of the trans¬ 
ducers are insulated from the target body. 

An amplifier that will operate satisfactorily 
with the SR-2 practice target must deliver con¬ 
siderable power to drive the projector. This 
necessitates the charging of the batteries after 
each day’s operation (8 to 10 hours). For con¬ 
venience, the batteries are therefore carried 
aboard the towing vessel, with a 12-volt in¬ 
verter to supply alternating current to the type 
U2-AB amplifier. Table 1 gives specifications to 
which this amplifier has been built. 

The power for the U2-AB amplifier is sup¬ 
plied through the tow cable, an electric oil-well 
logging cable which has a central insulated 
7-strand conductor and which is attached to a 
winch for handling purposes. This same cable 
functions as the line for the remote gain con- 


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142 


PRACTICE TARGET EQUIPMENT 


Figure 11. Transducer mounting in target model SR-2. 



m'- 


RESTRICTED 













COMPARATIVE EVALUATION OF THE KR-1 AND RR-1 TARGETS 


143 


trol, the remote signal indicator, and the depth 
gauge indicator. Figure 12 shows how the vari¬ 
ous units of the equipment are connected, and 
Figure 13 is a schematic wiring diagram of the 


by the head of sea water. An electric oil pres¬ 
sure gauge calibrated in feet of sea water is 
used for this purpose. The motor pressure unit 
of this device is installed in the head of the 


-CENTER CONTACT 
ON PRESSURE UNIT 



P-IO 

P-l 

AO 
] BO 
CO 


1_1 

< CD O O 

oooo 


AMPLIFIER 

D-3203 


SC o 

LC O 


1—1 

4000 

OOOO 

P-5 

P-3 


f A O 

o W -1 

1 M KS 

Li 

C. D 



\ DO 


1 SEE 
^NOTE 

S W-2 . 


/ 


1200 FT. ELECTRIC CABLE 


CONTROL CABINET D-3203 



atd or' a 

P-20 

A1 H nCA 

TYPE 12 
INVERTER 

3 

O 13 
[ 

O 14 


P-19 
[ 13 O 


1 


P-21 P-10 [l^Jsj 


P-25 P-24 



Ol 

[ 

[ 

1 O 

O 

O 13 

q 

[ 

13 O 


02 


2 O 

- 

O 14 


14 O 


CONTROL 

UNIT 


O 14 

a 

O 13 


P-15 
114 O 


02 


O- 

CL, 


CL 2 
BY-4 


A BATTERY 12 V 

(2-6V BATTERIES IN SERIES) 


CL 4 



Figure 12. Interconnection diagram for target model SR-2. 


NOTE- 

6R0UN0 TRANSDUCER 
CABLE SHIELDS TO 
TRANSDUCER CASES 


U2-AB amplifier and power supply. A detailed 
analysis of the circuits will be found in the 
instruction manual prepared for use with the 
SR-2 target. 4 

The depth of the target can be measured by 
determining the pressure on the target caused 


target, and the dial gauge is located in the 
remote control cabinet (Figure 14). 

Since the only electric connection between 
the control cabinet and the target is through 
the tow cable, the depth indicator cannot be 
operated when the amplifier is in use. When 


RESTRICTED 





























































































































16-26 KC 0 P FILTER 


144 


PRACTICE TARGET EQUIPMENT 



RESTRICTED 


Figure 13. Schematic diagram of U2-AB target amplifier 










































































































































































































































COMPARATIVE EVALUATION OF THE KR-1 AND RR-1 TARGETS 


145 


the control switch (SW) is set at “depth indi¬ 
cator,” no power is delivered to the inverter, 
and the a-c relay on the amplifier chassis opens 
to the depth indicator position. The 12-volt 
battery is then connected to the depth gauge 
circuit. 

Towing Characteristics 

The SR-2 model was designed for two specific 
purposes, to be towed with a head depressor on 
a 25- to 50-ft cable in shallow water such as 
harbors, and to be towed without the head 



Figure 14. Remote control cabinet for target 
model SR-2. 


depressor on an 800- to 1,200-ft cable in deep 
water. 

In the first case the target is useful in the 
preliminary training of sonar operators aboard 
the attack ship. For this service the head de¬ 
pressor must be used in order to submerge the 
target to operating depth. A depressor angle 
of 15° is recommended, but any angle may be 
used which will give the desired submergence 
of the target. Care must be taken to prevent the 


target from striking submerged objects or the 
bottom. 

In the second case the attack ship can pass 
over the towing cable and make simulated at¬ 
tack runs on the target. The greatest cable 
length that is consistent with operating con¬ 
ditions should be used for this purpose, 1,200 ft 
whenever possible. On these runs the attack 
ship must pass sufficiently far astern of the 
towing boat to clear the cable. Under normal 
conditions this distance is 300 ft. It is also im¬ 
portant that the target depth be such that the 
attack ship will pass over it. 

It should be noted that the addition of the 
head depressor (Figure 11) produces a marked 
change in the towing characteristics. When the 
head depressor is not used, the submersion of 
the target depends on the downward drag of 
the cable. At low speeds the tension on the 
cable is small and the resultant downward 
force is insufficient to submerge the target. At 
somewhat higher speeds the target submerges. 
The experimental data presented in Table 2 


Table 2. Approximate operating characteristics 
of model SR-2 without head depressor. 


Cable length 
(ft) 

Speed 

(knots) 

Target depth 
(ft) 

700 

5 

18 

700 

6 

0 

800 

3% 

47 

800 

4 

41 

800 

5 

33 

800 

6 

27 

800 

7 

0 

900 

3% 

70 

900 

4 

62 

900 

5 

47 

900 

6 

32 

900 

7 

27 y 2 

900 

7 % 

20 

900 

8 

0 

1,000 

3 Yz 

92 

1,000 

4 

86 

1,000 

5 

68 

1,000 

6 

57 

1,000 

7 

0 

1,100 

3% 

80 

1,100 

4 

57 

1,100 

5 

43 

1,100 

6 

37 

1,100 

7 

0 


give the range of speeds for given cable lengths 
within which the target will be submerged. 


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146 


PRACTICE TARGET EQUIPMENT 




1 

15' 

T 


WITH HEAD DEPRESSOR - 30’-0" CABLE 

Figure 15. Typical towing arrangements for target model SR-2. 


When the head depressor is placed on the 
target, the effective planing area is increased 
so that the downward force due to the re¬ 
sistance of the water is increased. Figure 15 
and Table 3 give typical data on the streaming 
of the target when the head depressor is used. 



Figure 16. Practice target, model SR-5. 


Practice Target Model SR-5 

The model SR-5 practice target, developed by 
UCDWR, is a towed underwater echo repeater 
especially adapted for echo-ranging practice at 
slow speeds in shallow water. Its steel-plate 
body is a wing-like structure upon which two 


CJ-1 transducers are mounted. The associated 
amplifier (model S5-AB) and its 6-v battery 
power supply are located aboard the towing 
vessel. The target is towed by means of a 30-ft 
flexible steel cable attached to a tow point built 
into an extension of the upper transducer 
mounting cap. A 7y^-lb lead disk, attached to 
the lower transducer mounting cap, provides 
stabilizing ballast. 


Transducer and battery cables and a 30-ft 
flexible steel tow cable complete the equipment. 
A T^-lb lead disk provides stabilizing ballast. 
The model SR-5 practice target is shown in 
Figure 16. 

The target body is a wing-like structure built 
of 16-gauge steel plate and made watertight by 
welded seams. The flat surfaces of the body 
are internally strengthened against external 
pressure by five longitudinal rib members. A 
tube structure extends through the center line 
of the body from top to bottom and provides a 
framework for the transducer mounting caps. 
The stabilizing disk is attached to the lower 
transducer mounting cap; the tow point is built 
into an extension of the upper transducer 
mounting cap. 

The cap screws used to secure the transducer 
mounting caps in place (see Figure 17) are 
drilled throughout their entire length in order 
to allow the tubes to flood with sea water. This 


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COMPARATIVE EVALUATION OF THE KR-1 AND RR-1 TARGETS 


147 


Table 3. Approximate operating characteristics 
of model SR-2 with head depressor. 


Cable length 
(ft) 

Speed 

(knots) 

Depressor 
setting (angle 

from horizontal, Target depth 
degrees) (ft) 

20 

4 

15 

10 

20 

5 

15 

10.5 

20 

6y 2 

15 

11 

25 

4 

15 

10 

25 

5 

15 

11.5 

25 

6 

15 

12.5 

25 

6Vz 

15 

13 

32 

4 

15 

12 

32 

5 

15 

13.5 

32 

6 

15 

14.5 


flooding is necessary to prevent distortion of 
the uniformity of the transducer response pat¬ 
tern. 

In order to avoid turbulence immediately 
behind the transducer, mounting structures, 



Figure 37. Transducer mountings in target 
model SR-5. 

and the transducers themselves, a membrane- 
type fairing made of Vs in. thick neoprene is 


stretched over each mount and transducer (see 
Figure 17). Each fairing is free-flooding and 
does not materially affect sound transmission. 

Transducers used in the SR-5 practice target 
are type CJ-1, discussed earlier in this chapter. 

The amplifier is model S5-AB, which is al¬ 
most identical with model U2-AB used in the 
SR-2 practice target. Values and specifications 
for these amplifiers are given in Table 1. 
Power for the amplifier is supplied by a stand¬ 
ard 6-volt, 150-ampere-hour storage battery 
which, when fully charged, provides about 16 
hours of satisfactory operation. 

Towing Characteristics 

The SR-5 practice target body is so designed 
that it will dive immediately when towed 
through the water at any speed from 3 to 6 
knots. When the target is stabilized, the center 
line through the two transducers is vertical. 
The divided surface of the body performs the 
double function of providing both vertical and 
horizontal stabilization. The displacement of 
the target body in salt water, when it is sup¬ 
porting the three cables, provides an excess 
positive buoyancy of approximately 15 lb. 

The final target depth is determined by the 
length of the tow cable. This depth, measured 
from the bottom of the lower transducer to the 


Table 4. Operating characteristics of model SR-5 
at a speed of 4 to 6 knots. 


Length of cable 
in water 
(ft) 

Depth 

(ft) 

10 

9 

15 

12 

20 

17 

25 

22 

30 

27 


surface of the water, will have the values listed 
in Table 4 when the tow craft has a speed of 4 
to 6 knots. 


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Chapter 11 


TRAINING EQUIPMENT FOR ANTISUBMARINE WARFARE SONAR 
MAINTENANCE PERSONNEL 


T he main purpose of equipment designed 
specifically to aid in the training of ASW 
sonar maintenance personnel is to demonstrate 
or give practice in the testing of sonar gear in 
order to locate troubles or insure adequate per¬ 
formance. 

The advantages of being able to conduct 
such training in the laboratory or training 
school with simulated hydrophone signals, in¬ 
stead of being forced to rely on dockside or sea 
testing, are evident. A program to develop an 
artificial signal generator for bench-testing and 
demonstration was therefore carried on at the 
Harvard Underwater Sound Laboratory. Paral¬ 
lel developments, the sound injectors and the 
JP amplifier demonstrator were carried out by 
the New London laboratory for submarine 
sonar maintenance personnel. 

The devices designed primarily for testing 
purposes are covered in Division 6, Volume 18, 
and it may be useful to the reader to refer to 
that volume. A key unit in various types of test¬ 
ing apparatus is the inductive echo simulator, 
or projector simulator [PS] coils, used with 
sound gear monitors to simulate the signals 
sent or received by an actual sonar projector. 
PS coils have been adapted to and incorporated 
in various types of training equipment, includ¬ 
ing two of the devices described in this chapter. 

The first of these is the artificial sonar pro¬ 
jector, designed to train ASW sonar mainte¬ 
nance men in testing the frequency response 
and directivity patterns of sound projectors. 

Following discussion of the artificial sonar 
projector, the hearing deviation indicator 
[BDI] dynamic demonstrator, an enlarged 
working model of the BDI wiring schematic, is 
explained. It is used to aid maintenance per¬ 
sonnel in mastering the circuits and learning 
how to take voltage measurements and make 
operating adjustments. 

The next section of the chapter gives an 
account of the signal generator designated op¬ 
erator training equipment, Model 9 (OTE-9). 
Although any signal generator with a fre¬ 


quency range from 18 to 25 kc may be used to 
activate the BDI dynamic demonstrator, OTE-9 
was designed especially for use with this unit 
and also with regular BDI units in the teaching 
of trouble-shooting. This is the second of the 
maintenance training devices incorporating 
PS coils. The final section briefly describes the 
equipment for submarine maintenance per¬ 
sonnel. 



Figure 1. Artificial projector and case. 

Artificial Sonar Projector 

The artificial sonar projector, developed by 
HUSL, consists essentially of a one-third-scale 
mockup of a spherical sonar projector and a 
special coupling unit called projector simulator 
[PS~\ coils. Other components are a frame to 
support the “exciter” coil and the hearing scale 
and a carrying case. The PS coils, when used 
with a signal generator and an output indicator, 
will give measurements illustrative of the fre¬ 
quency response and directivity patterns of 
either magnetostrictive or crystal split or un¬ 
split sonar projectors. 


111 INTRODUCTION 

Early attempts to obtain a realistic artificial 
signal for testing purposes led to the use of 


148 


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THEORY 


149 


disk reproduction of actual signals received 
during echo-ranging operation with QC gear. 
Since this was not satisfactory, the development 
of a completely artificial signal source was 
undertaken. To meet the requirements imposed 



Figure 2. Array of point hydrophones. 

in making directivity tests with BDI gear, first 
a simple RC phase-shifting arrangement was 
developed to provide two echo signals, differing 
in phase by a known and controllable amount. 



right. 

This was then discarded in favor of a more 
satisfactory method, utilizing the characteris¬ 
tics of mutual induction between two flat coils, 
one of which slides laterally across the face of 
the other (PS coils). 1 

As incorporated in the artificial sonar pro¬ 
jector, a single exciter coil mounted in a fixed 
position alongside a hollow, rotatable, wooden 
sphere, receives input signals from an external 
generator. Within the sphere’s surface, a group 


of pickup coils is so arranged that rotation of 
the sphere will result in lateral motion of the 
individual pickup coils across the face of the 
external, exciting coil. The induced voltages in 
a pair of quadrature pickup coils are combined, 
through a suitable phase-shifting arrangement, 
with the voltage set up in a single amplitude 
pickup coil to give an output simulating the 
response of a directional projector. The remain¬ 
ing coils of the group, controlled by a switch, 
are so mounted that the minor lobes, character¬ 
istic of a poor projector, can be secured when 
desired. 


THEORY 


In devising the PS coil arrangement, the out¬ 
put of an actual sonar projector was analyzed 
into a set of voltage vectors and the directivity 


Figure 4. 



effects on magnitudes and phase angles were 
determined. The possibility of using the varia¬ 
tion in mutual induction between coils to obtain 
duplication of this output was then recognized 
and design details were worked out experi¬ 
mentally. The procedure followed is summarized 
below. 

Outputs of Projector Halves 

Point Projectors. Consider first the idealized 
case of two identical nondirectional point hydro¬ 
phones L and R (Figure 2) separated by a 
distance l which is of the order of magnitude 
of one wavelength of sound. If a plane wave 
approaches along a direction making an angle 
y with the normal to the line LR, the voltages 


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150 


TRAINING EQUIPMENT—ASW SONAR MAINTENANCE PERSONNEL 


generated in the two hydrophones will differ 
in phase by an amount 6 given by the equation, 


e 



360 sin 7 degrees, 


where X is the wavelength of sound. It is convenient 
to express phase with reference to that in a third 
point hydrophone C located at the mid-point 
between L and R. If 7 is measured clockwise from 
the normal to the direction of the incident sound, 
in line with Navy practice, then for small positive 
values the phase of the voltage V L generated in L 
lags V c , that in C, by 6/2 ; similarly, Y R leads Vc 
by 6/2. These vectors are shown in Figure 3, in 
which a lead is represented by an anticlockwise 
rotation from the reference, V c . Since the hydro¬ 
phones are nondirectional, the magnitudes of the 
voltages generated are independent of 7 , so that 
Y r = Yl = Vc in magnitude. Consequently Y T , 
the vector sum of Yr and V l, is always either in 
phase with V c , or 180 degrees out of phase, 
regardless of the intensity of the signal or the 
direction of approach. For sound approaching 
from the left (7 negative) Y L leads Y c and Yr 
lags Vc, but V r remains in phase (+ or —) with 
V c . 


Outputs from Halves of Uniform Line 

If the nondirectional hydrophones are replaced 
by the halves of a uniform-line hydrophone extend¬ 
ing from R to L (Figure 2), the phases of the out¬ 
puts of the halves will be the same as those of two 
nondirectional hydrophones, one located midway 
between L and C and the other midway between 
R and C. This is because the line may be con¬ 
sidered as a row of point hydrophones, each 
generating the same voltage, the phase of these 
voltages differing from that of V c by amounts 
proportional to their distances from C. 

These voltages add vectorially into Y R and Y L , 
as in Figure 3, and V R and V L have the phase 
relationship associated with the mid-points of the 
halves. The magnitudes of these vectors do 
depend upon direction, since the line hydrophones 
have definite directionality. 


Outputs from Halves of a Circular 
Projector 

A typical sonar projector with a circular face, 
electrically split for BDI operation, behaves like 


the split line except that the directivity pattern 
of a half-circle differs from that of a uniform line, 
and the effective distance between halves is the 
distance between the acoustical centers of the two 
halves. With these qualifications, it is possible 
to speak of voltages Y R and Y L with phase de¬ 
pendent on 7 , but with amplitudes also depending 
on 7 because of the directionality of the projector 
halves. 

In-Phase and Quadrature Components. The 
electromotive forces V R and Yl of the two halves 
of a circular projector excited by a plane wave of 



sound may be resolved into components in phase 
with and at right angles to Vc, the hypothetical 
electromotive force at the mid-point, as shown in 
Figure 4. In this figure the in-phase components 
have subscripts I and the ones normal to them, 90 
or 270 degrees out of phase with Vc, have sub¬ 
scripts Q. 

The dependence of the amplitudes on the angle 7 
depends, as stated before, on the directivity 
patterns of the halves. On the basis of typical 
projector patterns (16 degrees wide, 10 db down 
for the unsplit projector) the variation with 7 of 
the magnitudes Yi R , Yil, Yq R and Yql is shown by 
Figure 5. These data were computed for a split 
circular projector of diameter 4X, which is ap¬ 
proximately equivalent to a nonshaded QC pro¬ 
jector at 24 kc. Shading, as well as a change in 
frequency, will produce only minor changes in the 


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SIMULATION OF OUTPUTS OF PROJECTOR IN RECEPTION 


151 


form of the curves, although the scale of 7 must be 
somewhat contracted to represent a wider major 
lobe. 

113 SIMULATION OF OUTPUTS OF 
PROJECTOR IN RECEPTION 

Production of In-Phase and Quadrature 
Voltages 

While various means may be used to control 
voltages in any desired way as a function of 
mechanical displacement, a suitable method is 
through variation of mutual inductance. If one 
coil of a pair carries alternating current, the 
voltage induced in a second coil will be pro¬ 
portional to the mutual inductance between them. 
The problem thus becomes essentially one of 
finding the constructional requirements of coil 
arrangements that will give the desired variation 
of mutual inductance with displacement. 


EXCITER 



Figure 6. Exciter coil, quadrature coils, and in- 
phase coil. 

It was found that an exciter coil with a radially 
distributed winding, moved laterally with respect 
to a similar pickup coil, gives a voltage curve 
almost exactly duplicating the V IR and Ytl curve 
of Figure 5 when plotted against displacement 
X. This displacement may be used to represent 
changes in 7 . Likewise the same exciter coil in 
conjunction with a pair of similar pickup coils 
connected in phase opposition gives voltage curves 
duplicating either the \ QR or \ QL curves of Figure 
5, depending upon polarity. By adjusting the 
sizes and numbers of turns in a combination of 
in-phase and quadrature pickup coils, as shown in 
Figure 6 , the required relationships between their 
respective outputs are achieved. 

Phase-Shifting Means 
The voltages induced in the in-phase (or 
amplitude) and quadrature coils are in phase 
agreement, but theory requires that they be 


combined in phase quadrature to give the de¬ 
sired results. A phase difference of 90 degrees 
must therefore be introduced. If operation is to 
be over only a very narrow frequency range, 
the 90-degree phase shift can conveniently be 
obtained with a single lag-line type of phase 
shifter. If operation over a broader frequency 
range is required, it has been found desirable 
to use a lead-lag combination. A 45-degree lead 
line is inserted in the output line from the 
amplitude coil and a 45-degree lag line in the 
output from the quadrature coil. As the fre¬ 
quency changes, the changes in the phase shifts 
of these lines are approximately complemen¬ 
tary, so that a difference of close to 90 degrees 
is maintained over more than an octave. 

Combining Circuit 

The simplest method of combination is 
through series connection. When the projector 
to be simulated uses the parallel split connec¬ 
tion of two halves (i.e., voltages in phase with 
respect to the common return for sound ar¬ 
riving on the axis), it is convenient to adjust 
the output of the quadrature coils to double the 
required value and to use a center-tapped re¬ 
sistor as the terminating impedance for the 
phase shifter. The center tap is connected 
through the amplitude coil circuit to the out¬ 
put common terminal and the ends are con¬ 
nected through isolating resistors to the output 
R and L terminals. When a series split pro¬ 
jector is to be simulated, the output of the 
amplitude coil is made double and is center- 
tapped. 

Method of Obtaining Required Frequency 
Response 

The required frequency response is obtained 
by tuning the exciter coil circuit so that the 
current through it varies properly with fre¬ 
quency. Since the voltages induced in the pickup 
coils vary directly with the current through the 
exciter coil, the required variation of projector 
output voltage with frequency is obtained. To 
simulate the frequency response of a magneto¬ 
striction projector, the exciter coil may be series- 
tuned with a suitable capacitor. Sharper reso¬ 
nance may be achieved with an additional 
high-Q coil in the series circuit. Leaving the 


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152 


TRAINING EQUIPMENT—ASW SONAR MAINTENANCE PERSONNEL 


exciter coil untuned results in the flat re¬ 
sponse characteristic of most types of crystal 
projectors. 

114 SIMULATION OF PROJECTOR IN 

TRANSMISSION 

In making measurements on the transmitting 
properties of an actual transducer, power is 
fed to the projector, and the voltage output of 
a hydrophone at a distant point in the water 
(preferably not less than four projector di¬ 
ameters distant) is observed. Combination of 
the sound pressures produced at the hydro¬ 
phone by the different elements of the projector 
gives a resultant pressure which depends upon 
the orientation of the projector. The output 
voltage of the hydrophone accordingly varies 
with projector rotation, and its measurement 
yields the transmitting directivity pattern. 

In order to simulate the foregoing process 
with the artificial projector, the operating func¬ 
tions of exciter and pickup coils may be inter¬ 
changed. The output terminals of the PS coil 
arrangement may be connected to a signal 
source, and voltages will be induced in the 
exciter coil. In this case, since the unsplit con¬ 
nection is used, the two high sides of the PS 
coil arrangement are connected together and 
since equal currents then flow through the quad¬ 
rature coils, their effect vanishes. The direc¬ 
tivity pattern, as in the case of the unsplit 
receiving connection, is therefore determined 
entirely by the geometry of the amplitude coil 
and the exciter coil. 

115 CONSTRUCTION OF ARTIFICIAL 

PROJECTOR 

The artificial projector pictured in Figure 1 
consists of the following. 

1. A model spherical projector unit which 
contains the projector simulator coil assembly 
and associated circuits. 

2. A frame which supports the exciter coil 
and bearing scale and on which the model pro¬ 
jector unit is mounted. 

3. A carrying case. 


4. Cables for connecting the projector with 
the associated equipment. 

The projector unit is a hollow wooden sphere 
(see Figure 1) designed to be a one-third scale 
model of a standard spherical sonar projector 
of the QC type. It can be rotated about a ver¬ 
tical axis and a bearing scale indicates the de¬ 
gree of rotation. 

Located inside the sphere is the PS coil 
assembly which comprises amplitude and quad¬ 
rature pickup coils, phase-shifting means, and 
a combining circuit. As the artificial projector 
is rotated, the amplitude and quadrature pickup 

QUADRATURE COILS 
52 0 TURNS NO.37 SCE 

1 4 x 8 °N 2 BAK C0RE EXCITER COIL 



Figure 7. Top cross-sectional view of artificial 
projector. 


coils approach and pass an energized exciter 
coil (see Figure 1) mounted just outside the 
wooden sphere. As this occurs, varying voltages 
are induced in the pickup coils and are then 
fed into the phase-shifting and combining cir¬ 
cuits, producing the main and minor lobes of 
the directivity pattern. The pickup coils are 
designed to give the same major beamwidth 
as that found in the directivity pattern of a QC 
projector that resonates to a similar frequency. 
The construction of these coils and their rela- 


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TYPICAL OPERATION 


153 


tive locations are shown in Figure 7. A switch 
is provided for cutting in additional amplitude 
coils to produce spurious side and back lobes. 

The exciter coil is mounted on a Lucite plate 
which is an integral part of the frame. The 
magnetic field of this coil induces voltages in 
the pickup coils within the sphere as described 
above. The impedance of the exciter coil is 
approximately 100 ohms and a type OAX sound 
gear monitor 2 can therefore be readily used 
as the signal source. The input connection to the 



Figure 8. Circuit diagrams for (A) the arti¬ 
ficial QC projector and (B) the artificial QJ split 
projector. 

exciter coil is made to an AN connector mounted 
on the base of the frame. 


For an artificial QC magnetostriction pro¬ 
jector, a single 90-degree lag line is used as the 
phase-shifting component to produce the re¬ 
quired quadrature phase relationship between 
the voltages of the amplitude and the quad¬ 
rature coils. It is housed within the model 
projector with the combining circuit, which is 
simply a center-tapped resistor and two isolat¬ 
ing resistors. The output connection is an AN 
connector mounted on the vertical axis of rota¬ 
tion of the projector (see Figure 1). A schematic 
wiring diagram for the artificial QC projector 
is shown in Figure 8A. By tuning the exciter 
coil, the projector is made to give a frequency 
response similar to that of an actual QC pro¬ 
jector. The center frequency of the projectors 
built at HUSL is approximately 21 kc. 

To simulate the frequency response of a QJ 
(split crystal) projector, the exciter coil is left 
untuned and the phase-shifting means consist 
of a 45-degree lead line and a 45-degree lag 
line. This arrangement yields a phase difference 
which is essentially 90 degrees over a wide 
frequency range. Figure 8B is a schematic 
wiring diagram for this artificial unit. 

When the artificial projector is connected to 
simulate the transmission function, signals are 
applied to the pickup coils in the sphere, and 
an output voltage is obtained from the exciter 
coil. Since only passive components are used, 
this voltage will vary with rotation of the pro¬ 
jector in accordance with the same directivity 
pattern as that obtained in the receiving func¬ 
tion. The frequency response will likewise be 
similar to that which obtains in reception. 

The artificial projector equipment weighs 15 
lb and measures 10x15 in. when enclosed in its 
carrying case. The top of this case also houses 
the necessary connecting cables (see Figure 1). 


11.6 TYPICAL OPERATION 

Unsplit Projector Patterns 

Frequency Response Curves. The artificial 
projector has one resonant frequency at which 
its power transmission is a maximum. This 
frequency, together with the Q of the device, 


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TRAINING EQUIPMENT—ASW SONAR MAINTENANCE PERSONNEL 


154 


can be determined from a transmission fre¬ 
quency-response curve. 

To obtain such a curve, a calibrated signal 
generator may be connected to the rotatable 
pickup coils while an output indicator is driven 
from the fixed exciter coil. (It is worth noting 
here that the present form of the device cannot 
safely handle the output of a high-power signal 
source.) The Q can be found from the response 
curve obtained by using the formula 

Resonant frequency (kc) 

Width of curve (kc) 3 db below peak 

If the signal generator is changed to the ex¬ 
citer coil and output indications are taken from 
the pickup coils, the resonant frequency and Q 



Figure 9. Frequency response curves at bear¬ 
ing 000°. 


for the reception function can be determined 
in similar fashion. Figure 9 shows typical 
curves for both transmission and reception. 

Directivity Patterns. To obtain transmitting 
directivity patterns, a signal may be applied to 
the internal pickup coils, and the output read¬ 
ings then obtainable from the fixed exciter coil 
as the projector sphere is rotated will give the 
information required. As before, the corre¬ 
sponding reception readings can be secured by 
interchange of the signal generator and output 


indicator locations. Figure 10 shows a poor 
pattern resulting from the use of the spurious 



Figure 10. Transmitting pattern with spurious 
lobes in. 


lobe coils, whereas Figure 11 portrays the 
ideal pattern which may be secured when these 


330* O 30° 



Figure 11. Receiving pattern with spurious 
lobes shorted out. 


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CONCLUSION 


155 


spurious lobe coils are shorted out of the circuit. 117 CONCLUSION 


Split Projector Patterns 
The displaced directional patterns typical of 



Figure 12. Circuits of artificial projector and 
BDI input. 


The artificial projector in its present form is 
adequate for simulating the performance of 
existing sound projectors. It is relatively simple 
to build a satisfactory model with electrical 
characteristics resembling almost any type of 
split or unsplit sonar projector. Future, more 
complicated, projectors may require modifica¬ 
tion or additional development of the device. In 
view of the continuing need for adequate per¬ 
sonnel training equipment, such development 
is recommended. 


330 ° 0 30 ° 



Figure 13. Receiving pattern as split projector 
with BDI lag line. 


split projector operation can be simulated with 
the artificial projector when it is used with a 
suitable lag line. Figure 12 shows the manner 
in which the input circuit of a standard BDI 
may be utilized for this function. The individual 
lobe patterns are obtainable by taking outputs 
from the opposite ends of the line (points A 
and C), while an undisplaced pattern will fol¬ 
low if the output is drawn from the center tap 
(point B). Figures 13 and 14 show results 
secured with a standard BDI lag line and with 
a split projector test unit [SPTU] lag line, re¬ 
spectively. 


330 ° 0 30 ° 



Figure 14. Receiving pattern as split projector 
with SPTU. 


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156 


TRAINING EQUIPMENT—ASW SONAR MAINTENANCE PERSONNEL 



Figure 15. BDI dynamic demonstrator—front view. 


BDI Dynamic Demonstrator 

The BDI dynamic demonstrator, developed by HUSL, is an enlarged working model of the 
BDI circuit diagram, with actual controls incorporated in it. A signal may be injected to demon¬ 
strate the operation of the circuit and the method of making adjustments. This display unit has 
been useful primarily in teaching sound maintenance men the X-3 BDI circuit and how to keep 
it in adjustment. 


118 INTRODUCTION 

The BDI dynamic demonstrator was de¬ 
veloped to meet the need for a large classroom 
display schematic of the BDI which would show 
the circuit not only in a static but also in a 
dynamic condition. This involved enlarging and 
rearranging the regular book schematic to 
permit mounting it on a board and incorporat¬ 
ing in it the various controls necessary to make 
it serve as a working model (see Figure 15). 

The demonstrator can be used for instruc¬ 
tion in step-by-step signal tracing and voltage 
and resistance measurements. It is also suited 
for laboratory experiments dealing with volt¬ 
age measurements, signal tracing, and operat¬ 
ing adjustments (including tuning and phasing 
input transformers, balancing, oscillator ad¬ 


justments, horizontal centering, focusing, ad¬ 
justment of range-start control, adjustment of 
range-limit control, intensity adjustments, 
range switch adjustments, and gain adjust¬ 
ments) . 

The BDI dynamic demonstrator was not de¬ 
signed for teaching trouble shooting, for which 
purpose an actual BDI unit is more suitable. 
Although the 7- and 10-kc filters can be aligned 
from the front panel, this should be done for 
maintenance of the demonstrator only, and not 
as a regular laboratory experiment. 

11 9 GENERAL DESCRIPTION 

The BDI dynamic demonstrator is a large 
X-3 schematic diagram drawn in colors on a 
6x3 ft panel on which are mounted and con- 


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CONCLUSION 


157 


nected the various resistors, condensers, tubes, 
coils, and other components which go to make 
up a standard X-3 BDI unit. Thus it consti¬ 
tutes a working model of the BDI unit in which 
the parts are arranged to conform to the 
schematic diagram rather than for ease of 
wiring, as is done in the actual BDI unit. For 
convenience in handling, the panel is mounted 
in a box 13 in. deep, which may be set on a 
table in front of the class (see Figure 15). 

The cathode-ray tube and a dummy BDI 1 ' 
panel are mounted in a separate box at the end 
of the larger one, which is hinged so that the 
face of the tube may be turned toward the in¬ 
structor while he is making adjustments and 
may then be swung back into a plane parallel 
with the rest of the panel for demonstration 
purposes. 

The only facilities required for the use of 
the BDI dynamic demonstrator are a 110-volt, 
60-c source of alternating current and any sig¬ 
nal generator having a frequency range from 
18 to 25 kc. It is recommended, however, that 
the special BDI signal generator (OTE-9), de¬ 
signed for use with the unit and described in 
the next section, be employed. 

1110 CONCLUSION 

Eight units of the BDI dynamic demonstrator 
were constructed at HUSL. The first of these 
was of slightly different construction from the 
rest in that the cathode-ray tube and dummy 
BDI panel were mounted on the main panel. 
This Model 1 was tried out successfully by the 
West Coast Sound School and from the sug¬ 
gestions made there Model 2, described above, 
was developed. Model 2 then served as proto¬ 
type for the remaining six. 

This development has shown conclusively 
that large-scale working models of schematic 
wiring diagrams can be used effectively in 
connection with quite complicated electronic 
equipment. Their value as teaching aids has 
been amply proved through the use of the BDI 
dynamic demonstrator in Navy sound schools 
and materiel schools. 

a For a complete discussion of the theory and opera¬ 
tion of BDI circuit, see Division 6, Volume 15, Chapter 
5. 



Figure 16. OTE-9 (BDI signal generator). 

Bearing Adjustment Signal Generator 

[OTE-9] 

The BDI adjustment signal generator, alter¬ 
natively called operator training equipment 
model 9 [ OTE-9], was designed by HUSL to 
serve as a signal source for demonstrating BDI 
action with either a BDI dynamic demonstrator 
board or a standard BDI unit. The complete 
OTE-9 equipment is contained in a two-unit 
metal case; one part of the case houses the 
OTE-9 electronic unit, and the other provides 
space for carrying cables and other accessories. 
The electronic unit furnishes either continuous 
or echo-like signals, and sweep relay keying 
pulses for the associated BDI equipment. The 
signal frequency is variable from 17 to 26 kc; 
the output level may be adjusted from 0 to 30 
mv. A set of projector simulator [PS] coils is 
used to produce a varying phase difference be¬ 
tween the two halves of the signal to simulate 
bearing deviation. No provision is made for 
simulating reverberation deflections on the BDI 


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TRAINING EQUIPMENT—ASW SONAR MAINTENANCE PERSONNEL 


screen, since they are not considered absolutely 
necessary for the purpose in view and their 
omission permits considerable simplification of 
the design. 


1111 INTRODUCTION 

During the program of development of bear¬ 
ing deviation equipment at HUSL, various gen¬ 
erators were constructed to provide signals for 
purposes of demonstration, training, test, and 
alignment. Some of these were designed to 
offer realistic simulation of reverberation, 
noise, and echo effects. For the purpose of 
alignment and adjustment alone, however, these 
requirements could be simplified. 

The device here described, OTE-9, is a sim¬ 
plified signal generator intended to provide 
either continuous or echo-like signals suitable 
for obtaining right or left deflections on the 
BDI. It was designed in this simplified fashion 
primarily to serve as a signal source for the 
BDI dynamic demonstrator, although it may 
also be used to generate test signals for any 
routine adjustments of BDI equipment. 

The specific requirements set up for OTE-9 
were as follows. The signal furnished should 
have a frequency adjustable over the range 
of 17 to 26 kc, an amplitude adjustable from 0 
to 3 mv for a bearing deviation of 0 degree, 
an echo with a duration of 65 yd at 1,000-yd 
range, and the possibility of manual control 
of the signal by using a test key. The unit’s pro¬ 
jector-simulator directivity should be gradu¬ 
ated in terms of a standard QC projector and 
limits for deviation test points should be pro¬ 
vided. The output impedance of the signal 
source was to be 200 ohms resistive per pro¬ 
jector half. Finally, the generator was to pro¬ 
vide a d-c pulse to operate the BDI sweep relay 
at a 2,000-yd range scale rate. 


1112 GENERAL DESCRIPTION 

A two-unit metal case, as shown in Figure 
16, houses all OTE-9 equipment. All controls 
and cables are mounted on the front panel of 
the electronic unit. The oscillator can be tuned 


by means of a calibrated dial over the fre¬ 
quency range from 17 to 26 kc, and the output 
level can be varied from 0 to 30 mv. Switches 
are provided for a-c power, for selection of a 
continuous output signal or a delayed-echo pulse 
simulating 1,000-yd range, and for BDI setting 
(left, center, or right). In addition, a push¬ 
button instantaneous contact switch is included 
for use as a test key to produce abrupt varia¬ 
tions in signal level for adjustment of the BDI 
balance control. 

Also on the front panel are receptacles for 
a-c power input, for supplying a-c power to the 
BDI, and terminals for supplying the signal 
input to the BDI and the keying pulse to the 
BDI sweep relay. 



Figure 17. OTE-9, electronic unit removed from 
housing. 

Figure 17 is an interior view of the elec¬ 
tronic unit. The PS coil assembly is in the 
center immediately behind the bearing devia¬ 
tion control knob, which is used to turn the 
exciter coil left or right. 


1113 DESCRIPTION OF CIRCUIT 

The circuit diagram for OTE-9 is shown in 
Figure 18. The oscillator, V-101A, is a con¬ 
ventional cathode-stabilized type that uses one 
half of a 6SN7 tube. The other half of the 
6SN7 (V-101B) is used as a cathode follower 
to isolate the oscillator and to provide a low- 


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DESCRIPTION OF CIRCUIT 


159 



impedance match for the projector simulator 
coils, discussed in Section 11.2. The coupling 
resistance is a 2,000-ohm potentiometer that 
is used to control signal level. 

The output of the cathode follower goes to 
two sets of switch contacts, connected in paral¬ 


lel, that allow control of the signal reaching 
the projector simulator (PS) coils. The first 
switch, S-104, on the panel, is an instantaneous 
type used as a test key to give signal pulses for 
adjustment of BDI balancing. The second set 
of contacts, S-103, is operated by the motor- 


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160 


TRAINING EQUIPMENT—ASW SONAR MAINTENANCE PERSONNEL 


driven cam M-101. This cam, shown in Figure 
17, first activates the BDI sweep relay to start 
the sweep through contact S-102, then sends a 
short delayed 65-yd echo pulse into the pro¬ 
jector simulator coils, L-102, L-103A, L-103B, 
and L-104, at approximately 1,000-yd range. 

In the OTE-9, the PS coils are mounted so 
that the exciter coil can be moved for bearing 
deviation by a knob on the front panel (see 
Figure 16). Detents are provided for centering 
the coils and for positioning them for standard¬ 
ized right and left deflections on the BDI. The 
detents can be removed to allow the coils to be 
swept freely from right to left deflection. The 
coils themselves are mounted on the chassis 
directly behind the panel. 

The lead-lag line assembly (shown schemati¬ 
cally in the center of Figure 18) acts as a 
phase-shifting circuit for maintaining the 
phase shift more nearly constant over the 17- 
to 26-kc frequency range than would be true 
if a single-section lead or lag line were used. 
Each of the two sections is designed to give a 
45-degree shift at the center frequency of the 
band to be used. The lead line is connected to 
the amplitude coils of the projector simulator 
coil assembly, while the lag line is connected to 
the quadrature coils; thus at center frequency 
the voltage from the amplitude coils is made 
to lead the induced voltage by 45 degrees, while 
that of the quadrature coils lags the induced 
voltage by 45 degrees, and the required 90-de- 
gree phase shift is obtained. Since the phase 
shift due to the lag line becomes larger with 
increasing frequency and that due to the lead 
line becomes smaller by about the same amount, 
the sum of the two remains approximately con¬ 
stant at 90 degrees (actually within 4 degrees 
over one octave). Resistors R-112 and R-113 
provide the necessary amount of voltage for 
the amplitude coils and give the loading on the 
coil necessary to correct the phase of the out¬ 
put. This correction is necessary, since the lag 
line with 2,000 ohms impedance, acting as a 
load on the quadrature coils which have a high 
internal impedance themselves, causes the 
terminal voltage to differ in phase from the 
induced voltage. 



Figure 19. JP amplifier demonstrator. 


JP Amplifier Demonstrator 

The JP amplifier demonstrator, developed by 
CUDWR-NLL, is a large wooden model (2 X /^ 
times actual size) of a JP-1 amplifier, mounted 
on a pair of trunnions so that it can be rotated 
about its long axis. On one side wooden replicas 
of the amplifier parts are mounted. On the 
reverse side, actual parts are incorporated in a 
circuit diagram, with interwiring to permit 
tests and voltage and resistance measurements. 
This reverse side can either be rotated to take 
the place of the chassis mockup or swung into 
position above it, as shown in the figure. A third 
side, representing the amplifier front-panel 
controls, is at the bottom in the figure. This 
panel can be swung into position to demonstrate 
correct operating procedures. This device is 
the main component of the JP training kits. 


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TRAINERS FOR SUBMARINE MAINTENANCE MEN 


161 


u, « CONCLUSION 

The BDI signal generator OTE-9 fulfilled a 
definite instructional need by furnishing a single 
instrument to which a BDI could be connected 
for demonstration, thus eliminating the need 
for a separate signal generator and keyer. One 
OTE-9 was constructed to accompany each BDI 
dynamic demonstrator board, but World War 
II ended before any decision was made to 
procure OTE-9 units in quantity to meet signal 
generator needs at locations where maintenance 
and repair work is carried on for BDI equip¬ 
ment. 


1115 TRAINERS FOR SUBMARINE 
MAINTENANCE MEN 

Special training for maintenance men who 
were to be responsible for submarine sonar 
gear paralleled the ASW sonar maintenance 
courses. Devices covered in this chapter, which 


were designed to facilitate submarine sonar 
maintenance instruction, are the trouble injec¬ 
tors and the JP amplifier demonstrator. 

Trouble Injectors 

Trouble injectors, designed and built by 
UCDWR-NLL are used ivith JP listening gear 
to set up a series of trouble-shooting problems 
for submarine sonar maintenance trainees. 
They also served with JP installations on 
the New London radar-sonar barge to simu¬ 
late troubles commonly encountered in JP op¬ 
eration, in order to test the operator’s alertness 
in noticing and reporting irregularities. A series 
of switches in a panel are so wired to the sonar 
gear that, when thrown, they have the following 
effects: thermal noise too high or too low; no 
thermal noise, but magic eye lighted; no thermal 
noise, magic eye not lighted; failure of magic 
eye to wink when magnetizing; failure of magic 
eye to close; failure of detector switch. 


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Chapter 12 

TRAINERS FOR AIRCRAFT PERSONNEL USING SONAR EQUIPMENT 


P rofiting by the experience gained when 
the expendable radio sono buoy [ERSB] 
was put into operation, CUDWR engineers at 
the New London laboratory paralleled the later 
stages of the development of the directional 
radio sono buoy [DRSB] with the evolution of a 
well-rounded training program, including the 
preparation of instruction manuals, course ma¬ 
terials of all kinds, phonograph recordings, and 
a training device intended to portray the nor¬ 
mal operational use of the directional buoy. 
The DRSB trainer is described in detail in 
this chapter. 

For the training of Navy aircraft personnel 
in the recognition of signals from the ERSB, 
the New London laboratory likewise constructed 
an ERSB trainer. Pictures of this device and 
references to related material are included 
here. 


Directional Radio Sono Buoy Trainer 

The directional radio sono buoy [D.RSB] 
trainer, developed by CUDWR-NLL, is a de¬ 
vice for supplying simulated submarine pro¬ 
peller and water noises, with appropriate range 
and bearing information, to a group of stu¬ 
dent operators in a manner closely approxi¬ 
mating reception of such information from a 
directional radio sono buoy. The trainer con¬ 
sists of a plotting board upon which a “sub¬ 
marine” moves over any desired course, an 
electronic sound generator supplying target 
signals, a mechanism for reproducing recorded 
background noises, and two FM transmitters, 
each representing a DRSB. The signal and 
noise outputs are mixed as desired and then 
broadcast by the FM transmitters to a number 
of student stations equipped with standard 
DRSB receivers. The student determines target 
bearing and propeller beat count. An instruc¬ 
tor's repeater enables the instructor to follow 
the course of a given problem and, through ear¬ 
phones, to monitor the output of either buoy or 
of any of the student receivers. 



Figure 1. Directional radio sono buoy trainer. 


121 INTRODUCTION 

Early in the development of the DRSB, it 
was apparent that the use of aircraft and the 
expenditure of considerable numbers of oper¬ 
ating DRSB units would be required if no 
shore-based training could be provided. On the 
other hand, if such training could be made 
sufficiently realistic, it was believed that one or 
two checkoff flights using standard equipment 
would suffice for most of the operating crews. 

The DRSB itself is a means of picking up 
submarine sounds on a floating rotating sonar 
hydrophone and transmitting the sounds by 
radio to an aircraft crew. For a complete under¬ 
standing of the trainer developed to prepare 
aircraft personnel to use this device, it is neces¬ 
sary that the principles of operation of the 
DRSB be understood, particularly the method 
of transmitting bearing information from the 


162 


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GENERAL DESCRIPTION 


163 


buoy to the receiver. The reader is therefore 
referred to Division 6, Volume 14, Chapter 9. 


12 2 GENERAL DESCRIPTION 

Figure 1 shows the main unit of the DRSB 
trainer, which contains the electronic sound 
generator for supplying target propeller noise. 
On one side of the unit is a turntable for intro¬ 
ducing recorded water noise. The top of the 
unit carries a plotting board on which the 
target submarine is represented by a crab. 


propeller sounds closely resemble the sounds 
heard from an actual submarine over the rotat¬ 
ing directional hydrophone of a DRSB, and 
the recording provides a realistic background 
of water noise. 

A second synchro and potentiometer arrange¬ 
ment, representing buoy No. 2, is mounted on a 
movable bridge over the plotting board. It may 
be placed in any direction and at any distance 
from 0 to 6,000 scale yd from buoy No. 1. This 
second buoy is also connected mechanically to 
the target crab, and its signals are sent out on 
a second transmitter adjusted to transmit on 
a different frequency from that of the first 





Figure 2. Block diagram of DRSB trainer. 


Through the controls on the instrument panel, 
this crab may be set to move on any course over 
the plotting board and at any of six speeds 
(2, 3, 4, 5, 7, or 9 knots) tracing its own course 
with a pencil stylus. 

A synchro and potentiometer arrangement in 
the center of the plotting board, representing 
buoy No. 1, is mechanically connected to the 
moving crab or target. As the target moves, the 
synchro alters the propeller noise signals for 
bearing, and the potentiometer alters them for 
range. The resulting radio signals sent out on 
buoy No. 1 transmitter thus correctly simulate 
the output of a DRSB, providing means for 
determining the bearing and range of the tar¬ 
get with respect to the buoy. The generated 


buoy. The two buoys may be operated simul¬ 
taneously for practicing triangulation if desired. 

Figure 2 is a block diagram showing the 
relationship of the different parts of the system, 
and Figure 3 is a detailed diagram. 

The radio signal transmitted is virtually the 
same as that transmitted by the working DRSB. 
It is a frequency-modulated carrier of around 
70 me, modulated to a maximum deviation of 
plus or minus 75 kc with an audio bandwidth 
of about 100 to 8,000 c. The carrier frequency 
is also deviated from its normal value to trans¬ 
mit directional information. 

The target-sound level may be adjusted to 
provide various degrees of sound output from 
the target; that is, it can represent a noisy or a 


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164 


TRAINERS FOR AIRCRAFT PERSONNEL USING SONAR EQUIPMENT 


quiet submarine. The water-noise level may 
also be adjusted to represent various sea con¬ 
ditions. 

A loudspeaker is mounted in the control panel 
for monitoring by the instructor or a group of 
students. A switch permits monitoring either 
buoy No. 1 or No. 2. A press-to-talk switch con¬ 
verts the loudspeaker into a microphone, so 


put of either buoy No. 1 or buoy No. 2, or the 
output of any of the twelve student receivers. 
He can also talk to any student over the inter¬ 
communication system circuit. When the stu¬ 
dent wants to initiate a conversation, he oper¬ 
ates a signal light on the instructor’s repeater 
unit by pushing a button at the operator’s 
station. 


RELATIVE 



Figure 3. Detailed diagram of DRSB trainer. 


connected that the instructor may talk through 
both transmitters simultaneously. This permits 
him to give necessary instructions over the air 
to all students tuned to either buoy. 

The instructor’s repeater unit, shown in Fig¬ 
ure 4, is usually mounted on a desk adjacent to 
the trainer. Its dials give the instructor con¬ 
tinuous readings on the range and bearing of 
the target from both buoys. By pressing the 
appropriate pushbutton on this unit, the in¬ 
structor can monitor with earphones the out- 


123 DETAILED DESCRIPTION OF 
OPERATION 

Signal Simulator System 

The noise source for the submarine propeller 
beats is a gas tube generating thermal noise of 
sonic frequencies (see Figure 3). This output 
is fed through a level adjustment to the stator 
windings of a 1-F synchro used as a variable 
transformer. Each revolution of the rotor of 
the 1-F develops two noise nodes simulating 


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DETAILED DESCRIPTION OF OPERATION 


165 


propeller beats. The rotor is turned by a vari¬ 
able speed motor, which is controlled by the 
same speed control as the target crab motor. 
The rotor speed is adjusted to give propeller 
beats at the rate of 25 for each knot of sub¬ 
marine speed. The target sound output is then 
split into two identical channels for buoy No. 1 
and buoy No. 2. After that the propeller beats 
are fed through a variable gain amplifier where 
the intensity of the signal is varied so that 
as the range increases the intensity of the signal 
decreases accordingly. The change in level is 
approximately 6 db per distance doubled, thus 
accurately representing average operating con¬ 
ditions. The signal is next fed into a filter unit 
where it is divided into three frequency chan¬ 
nels by means of a low-pass, a band-pass, and a 
high-pass filter. The low frequency channel is 
not further altered. The band-pass channel 
(around 4,000 c) is altered (by the synchro and 
the cams) to correspond to the beam pattern 
for middle frequencies. The high-pass channel 
is likewise altered. Each channel is then fed 
through a potentiometer where the relative lev¬ 
els of the three channels may be adjusted to 
simulate the actual buoy noises for each fre¬ 
quency band. 

The output of these three channels is fed to 
the mixer unit, where it is combined with the 
recorded water noise. The water-noise level can 
be varied independently to represent different 
sea states. This mixed signal of water noise and 
propeller beats is then amplified and fed into 
the buoy transmitter. 

Synchro Systems 

For each buoy channel there is a synchro 
system which changes the target signal accord¬ 
ing to bearing. This change takes into account 
two factors: the constant turning of the hydro¬ 
phone and the change in bearing caused by 
movement of the target. 

To simulate the turning of the hydrophone, 
there is a small motor rotating at 5 rpm which 
drives a pair of cams. Followers on these cams 
alter the position of the rotors in the 1-F syn¬ 
chros, which act as variable-gain audio trans¬ 
formers for the 4,000 and 7,000-c portions of 
the signal, thus simulating the directional pat¬ 
tern of the hydrophone. This motor drives a 


5-DG synchro, which is a differential generator. 
The 5-DG in turn drives a 1-F synchro located 
in the transmitter. The 1-F synchro carries a 
permanent magnet which, in rotating, turns a 
small compass-controlled condenser in the 
transmitter. This condenser varies in capacity 
with rotation and changes the mean carrier 
frequency of the transmitter just as is done in 
the DRSB. An early development model DRSB 
compass condenser is, in fact, used for this 
purpose. This sequence of operations is ad¬ 
justed so that when the target is, for example, 
on 000 degree true from buoy No. 1, the audio 



Figure 4. Instructor’s repeater for DRSB 
trainer. 


signal will “beam” when the receiver direction 
indicator is going through bearing 000 degree, 
or north. In reception, action of the receiver is 
identical with that of an actual operating DRSB 
signal. 

When the target crab is moved to a different 
bearing, the 5-G synchro to which it is mechani¬ 
cally connected is rotated through a correspond¬ 
ing angle. This synchro voltage is fed to the 
5-DG. The changed signal output from the 5-DG 
will, during the angular movement of the tar¬ 
get, be equal to its shaft speed of 5 rpm plus or 
minus the angular speed of the target around 
the buoy. The 1-F synchro rotating the magnet 
together with the condenser as indicated above 
and following this changing synchro voltage 
will speed up or slow down, thereby maintain¬ 
ing the proper phase relation with respect to 
the simulated hydrophone direction beam. 
Therefore, the transmitter signal will always 
give the hydrophone audio beam at the instant 


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166 


TRAINERS FOR AIRCRAFT PERSONNEL USING SONAR EQUIPMENT 


when the direction indicator is at the bearing 
of the target crab from the buoy. 

Monitor System 

Amplifier and Talk-Back. The monitor switch 
on the trainer is a single-pole, double-throw 
switch which enables the instructor to monitor, 
by means of the loudspeaker, the audio signal 
fed into either transmitter. As the combined 
target signal and water-noise signal comes 
from the mixer it is fed not only into the trans¬ 
mitter but also through a potentiometer which 
adjusts the level of the signal and then on 
through an implifier into the loudspeaker. 
When the press-to-talk switch is pressed down, 


it disconnects the signal into the transmitter 
and connects the speaker as a microphone to 
the input of the amplifier. The output of the 
amplifier is then switched to both buoy trans¬ 
mitters. The instructor’s words go through the 
amplifier and into the transmitters, where they 
are sent out to the receivers. 

Play-Back. The recorded water noise goes 
through the phonograph preamplifier and on 
through the potentiometer, which provides an 
adjustment for the water-noise level. From 
here the noise is fed into both mixer units. 

The alternating current on the turntable is 
not connected to the master switch, so that the 
turntable operates independently of the master 
switch. 



. 


Figure 5. Expendable radio sono buoy trainer. Figure 6. Transmitters for ERSB trainer. 

Expendable Radio Sono Buoy Trainer 

The expendable radio sono buoy trainer [ ERSB ], developed by CUDWR-NLL, consists of a 
bank of four turntables and four reproducers to simulate from recordings the sounds of sub¬ 
marines received by radio from ERSB’s laid down in patterns on the ocean surface. Figures 5 
and 6 give a general idea of how the equipment was set up. For a complete description of the 
ERSB itself, see Division 6, Volume 11+, Chapter 9. 


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Chapter 13 

MISCELLANEOUS TRAINERS AND DEMONSTRATORS 




Figure 1. Primary conning teacher, conning 
position. 


Primary Conning Teacher 

The 'primary conning teacher \_PCT~\ is a de¬ 
vice for training conning officers to use infor¬ 
mation obtained from echo-ranging equipment 
to plot the course of a surface vessel through¬ 
out an attack run upon a submarine target. At 
one end of the machine, target range and bear¬ 
ing information are optically presented on a 
screen at realistic intervals, and engine and 
rudder controls are provided to enable the con¬ 
ning officer trainee to change the speed and 
course of his ship accordingly. In a second con¬ 
trol station at the opposite end of the machine 
is a “submarine commander” who controls the 
speed and course of the simulated submarine 
target. One model of the conning teacher, desig¬ 


nated model Bl, simulates the action of a fast 
ship with a comparatively large turning circle, 
whereas another version, model B2, simulates 
a slower ship with a small turning circle. The 
complete instrument weighs 70 lb and is con¬ 
tained in a metal cabinet measuring 12x16x23 
in. It operates from a 110-v, 60-c power supply 
and requires a current of approximately 3 
amperes. The PCT was originally built at the 
University of Pennsylvania and later was 
modified and improved by UCDWR. 

T he usual attack teacher operation was too 
complex to provide elementary training in 
methods of plotting own-ship’s course. The de¬ 
velopment of the primary conning teacher, 
however, made it possible to hold extensive 
drills in plotting, with continuous increase in 
the level of difficulty. Students could thus be 
brought to the point where they could plot effi¬ 
ciently when using attack teacher information 
and during their sea training. 

Most of the attack teachers in use during 
World War II were not equipped to provide 
bearing deviation indicator [BDI] bearings. 
The conning teacher, by furnishing accurate 
ranges and bearings at regular intervals, simu¬ 
lates BDI conditions with considerable fidelity 
and thus also gives students excellent training 
in this phase of interpreting conning instruc¬ 
tions. 

The principles of operation in Models Bl and 
B2 of the conning teacher are the same and are 
described below. 


131 PRINCIPLES OF OPERATION 

The conning officer trainee is seated at one 
end of the instrument and imagines his ship 
to be at the center of the screen on the panel 
before him (see Figure 1). The range (2,000-yd 
maximum) and bearing of the submarine tar¬ 
get are indicated to him by a small round light 
spot which appears intermittently on the screen. 
The frequency with which the spot appears is 


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167 






168 


MISCELLANEOUS TRAINERS AND DEMONSTRATORS 


approximately that at which he could expect 
to obtain information from a good sound oper¬ 
ator. Likewise on the panel are engine and 
rudder controls with which the conning officer 
can change the speed and course of his ship. 
Delays are incorporated in the rudder control 
to simulate the lag in the ship’s response to 
the helm; the rate of turning is also a function 
of the ship’s speed. Turning rates were selected 


rine) to be at the center of his screen on the 
course indicated by the course dial. A continu¬ 
ous light spot on the submarine screen here 
portrays the movement of the destroyer with 
respect to the submarine and is calibrated for 
bearing but not for range. Controls for chang¬ 
ing the speed and course of the submarine are 
provided and also appropriate delays and turn¬ 
ing rates. 

At the beginning of each run the problem- 
setter sets the light spot and thereafter pro¬ 
vides the conning trainee with additional 
information in accordance with the desired ex¬ 
ercise. The exercises can vary from the simple 
case in which the trainee is given a constant 
speed and course for the submarine to exercises 
where the problem-setter regards himself as a 
submarine commander and employs all the eva¬ 
sive tricks at his command to avoid destruction. 

It is possible to apply various criteria of 
judgment in evaluating an attack. For example, 
the scoring of a mousetrap problem might be 
made on the ability of the conning officer to 


Figure 2. Primary conning teacher, submarine 
position. 


so as to be appropriate for an average ship of 
the class which the instrument is intended to 
represent. Ship’s speed is controllable without 
time lag. 

When the device is in normal use as an ele¬ 
mentary conning trainer, a problem-setter occu¬ 
pies the instructor’s or submarine position (see 
Figure 2). He imagines his ship (the subma¬ 


Figure 3. Primary conning teacher, side view 
showing auxiliary control panel. 

maneuver his ship so as to be on the correct 
bearing at the instant of “fire,” or, in another 
case, the conning officer might be held responsi¬ 
ble for the time of fire as well as for the correct 
ship’s course. 

With the conning teacher it is possible to 
provide exercises to which such different cri¬ 
teria may be applied. These exercises include 




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"°—» 


NOTES 

1 MODEL B1 WIRING AS SHOWN 
MODEL B2 WIRING USE TAPS 7-8- 
INSTEAD OF TAPS 7-9-10-11 


R-l 200 OHMS 
R-2 350 OHMS 
R-3 OPEN 
R-4 100 OHMS 

R-l 150 OHMS 
R-2 200 OHMS 
R-3 1000 OHMS 
R-4 75 OHMS 



Figure 4. Electrical schematic for the primary conning teacher. 


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CONCLUSION 


169 


preliminary and advanced plotting instruction, 
depth charge attack (with BDI) on straight- 
course submarine, forward thrower attack 
(with BDI) on straight-course submarine, 
depth charge attack (with BDI) on maneuver¬ 
ing submarine, and forward thrower attack 
(with BDI) on maneuvering submarine. 

13 2 GENERAL DESCRIPTION 

The primary conning teacher is shown in 
Figure 3. A complete electrical schematic 1 for 
the teacher is given in Figure 4. 

Optical Unit. The target spots for the de¬ 
stroyer and submarine screens are obtained by 
the light from a Mazda No. 1129 bulb passing 
through an 0.008-in. diameter hole in a thin 
diaphragm in the lamp housing, through a 
double convex lens, and on to a movable front¬ 
surfaced mirror from which it is reflected on¬ 
to the screen. Each screen consists of a scale 
printed on translucent paper secured between 
two Lucite disks. The scales are adjustable to 
permit alignment of the destroyer and the sub¬ 
marine scales independently. The light sources 
are energized from transformer T-3 when the 
power and light switches are on. 

The mirrors are driven by two watt-hour 
meters W-l and W-2, the former serving to 
rotate the mirrors about a horizontal axis and 
move the light spots vertically or North-South, 
and the latter to tilt the mirrors about their 
vertical axis and thus move the light spots 
horizontally or East-West. The voltage coil of 
W-l is energized by a variable voltage which 
is always proportional to the North-South com¬ 
ponent of the relative motion of the destroyer 
and the submarine. Similarly, the voltage on 
W-2 is proportional to the East-West com¬ 
ponent of the relative motion. 

Resistance potentiometers P-1 and P-2 are 
mounted on the steering motors M-l and M-2. 
Each of the potentiometers is center-tapped 
and is provided with two sliding contacts whose 
position is controlled by two cams mounted on 
the motor shaft. The cams are so shaped and 
oriented on the shaft that when the motor is 
turned to a given true course as indicated by 


the course dial the voltage between the center 
tap and the front (as viewed from the shaft 
end of the motor) contact is proportional to 
the East-West component of the ship’s motion 
on that course at the selected speed, whereas 
the voltage between the center tap and the rear 
contact is proportional to the North-South com¬ 
ponent of the motion. 

Destroyer Steering Motor Circuit. The de¬ 
stroyer steering motor M-l is a reversible, 
single-phase, shaded-pole motor. Speed changes 
are effected by inserting resistance in series 
with the shading coil windings. The rate of 
change of course (rate of turning of the motor) 
is a function of both the degree of rudder and 
the ship’s speed. The direction and rate of 
turning are both controlled by the DD control 
switch. A 12-sec delay period is provided by 
the time-delay tube V-l. 

Submarine Steering Motor Circuit. The sub¬ 
marine steering motor M-2 is controlled by the 
SS rudder control switch. Only full rudder is 
provided. The time-delay circuit, including V-2, 
is similar to that for the destroyer steering 
motor circuit, and provides a 15-sec delay 
going into a turn and a 5-sec. delay coming out 
of a turn. 

Barrage Release Circuit. When the depth 
charge release switch is momentarily closed, 
relay F-ll operates and signal lamp L-7 is 
lighted. 

The length of the time interval is 14.5 sec 
for the throw forward position, while for the 
drop astern position the time delay is 19 sec. 

133 CONCLUSION 

From all reports, the conning teacher satis¬ 
factorily met the need for a device to provide 
preliminary training for conning officers in 
antisubmarine attack methods. It was particu¬ 
larly well adapted to instruction in conning 
attacks with BDI. The fact that each perform¬ 
ance by the conning officer could be easily 
scored provided a convenient check on the prog¬ 
ress of the officer. One hundred and four units 
were procured by the Navy from the Sangamo 
Electric Company. 


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MISCELLANEOUS TRAINERS AND DEMONSTRATORS 


Magnetic Ocean Demonstrator 



Figure 5. Magnetic ocean demonstrator. 


It was a short time after the initiation of a 
lecture analysis program by UCDWR at WCSS 
that it was found that one of the greatest needs 
was effective visual aids. Among these was some 
type of simple demonstration for illustrating 
relative bearing and target angles and lead 
angle corrections in various kinds of antisub¬ 
marine attack situations. After tryouts of a 
number of models for this purpose, it was 
decided to use 8-in. antisubmarine warfare 
vessels and 6-in. submarine models, mounted 
by means of magnets on a 4x4 ft upright 
sheet. 

Although the visual aids project was initiated 
primarily for the officers’ course, “magnetic 
sea” units were constructed not only for the 
officers’ schools, but also for the operators’ 
schools. 


The magnetic ocean demonstrator is a class¬ 
room visual aid designed to illustrate the role 
of relative motion in various antisubmarine 
warfare situations. It consists of two 8-in. 
models of ASW vessels and one 6-in. model of a 
submarine mounted by means of magnets on a 
vertical iron sheet painted black. The submarine 
and one ASW vessel are each attached to 8-in. 
relative bearing disks and are maneuvered in 
conjunction with the disks. The submarine’s 
periscope and the forward part of the ASW 
ship’s bridge, both' mounted over the center of 
the respective disks, are attached by a taut 
string which demonstrates relative bearing and 
target angle. The unattached ASW vessel is 
likewise maneuverable and serves to give prac¬ 
tice in bearing estimation. The magnetic ocean 
demonstrator was developed by UCDWR. 


134 DESCRIPTION 

The submarine is so mounted that its peri¬ 
scope is in the center of the disk, and the ASW 
vessel is mounted so that the forward part of 
the bridge is in the center of the disk. 

A string, held taut by a small lead sinker runs 
from the periscope of the submarine (where it 
is secured by a bowline to allow it to rotate 
freely) through an eye on the forward part of 
the ASW vessel’s bridge. (Figure 5.) This ar¬ 
rangement results in showing at all times rela¬ 
tive bearing and target angle of submarine. 
A forward-throwing rack and depth charges 
mounted on each ship and painted black facili¬ 
tate instructions on lead angle corrections due 
to difference between sonar bearing and bearing 
from depth charges or forward throwers. 


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DESCRIPTION 


171 



the slide is in the 'projector. It is used to 
project a variable image on a screen in class¬ 
room demonstrations of search, sweeping 
target, and other sonar operator procedures. 


Figure 6. Relative bearing animated trainer. 

Relative Bearing Animated Trainer 

The relative bearing animated trainer 
[. RBAT ], developed by CUDWR-NLL, is a 
lantern slide representing a relative bearing 
scale with parts which can be moved while the 
slide is in the projector. An image of a ship 
appears in the center and another image of a 
target ship is so placed that it can be rotated 
around the central ship. A sliding shutter is 
used to conceal the relative bearing scale while 
a problem is set and students make a relative 
bearing estimation. The shutter is then with¬ 
drawn and the correct answer read. 



Figure 7. Bearing indicator animated trainer. 

Bearing Indicator Animated Trainer 

The bearing indicator animated trainer 
[. BIAT ], 3 developed by CUDWR-NLL, is a 
lantern slide representing the bearing repeater 
dials of a sonar stack, with controls which 
enable the instructor to vary the readings while 



Figure 8. OBR front view, cover open to show 
chart and stylus mechanism. 


Operational Bearing Recorder 

The operational bearing recorder [OBR], de¬ 
veloped by HUSL, is a sound range recorder 
modified to record both the actual projector 
bearings and the corresponding bearings called 
by the sonar student, so that by comparing the 
two tracers the student may study his errors 
and evaluate his progress in training under a 
variety of conditions and with different operat¬ 
ing techniques. A servo-synchro mechanism con¬ 
nected to the recorder stylus records the pro¬ 
jector bearings. A manually controlled stylus 
allows simultaneous recording of the bearings 
called by the sonar operator. The two traces 
are recorded on wax-coated paper moved at a 
constant speed by a clock-motor mechanism. 


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172 


MISCELLANEOUS TRAINERS AND DEMONSTRATORS 


135 DESCRIPTION 

In order to fill quickly the need for an in¬ 
strument that could make a graphic record of 
both actual sonar projector bearings and target 
bearings called by the sonar operator, a Barber- 
Coleman recorder already developed as a unit 
in an attack director was rebuilt to serve as a 
basis for the new device. In the OBR unit (see 
Figure 8), the Barber-Coleman recorder is so 
arranged that the string-driven stylus auto¬ 
matically records actual projector bearing, and 



Figure 9. OBR record, called bearings obtained 
from BDI. 

a second, tape-driven stylus, operated manu¬ 
ally, records called bearings. A sample OBR 
record is shown in Figure 9. The two traces 
are displaced about 2 seconds (vertically on 


the chart) with respect to each other because 
the points of the two styli cannot be brought 
closer together with the mechanical arrange¬ 
ment employed. 

To effect this arrangement, the following 
modifications were made in the original re¬ 
corder (see Figure 10). 

1. The Barber-Coleman recorder was modi¬ 
fied to provide a continuous record of actual 
projector bearings by removing the driving 
motor for the string-driven stylus and extend¬ 
ing the drive shaft through the back of the case 
where it terminated in a slotted disk a. A new 
string-driven stylus b that would pass in front 
of the manually controlled stylus was substi¬ 
tuted for the original one, and the tapping 
solenoid was disconnected so that the new 
stylus would record continuously. 

2. So that called bearings might be recorded, 
the shaft carrying the bevel gear and leading 
back to the synchro was removed, and the ball¬ 
bearing clamping nut on the top of the tape 
sprocket was replaced by a ^-in. shaft extend¬ 
ing through the top of the case and terminating 
in a bakelite knob shown at c. A felt washer 
was placed under the knob to prevent water 
from flowing into the case and to furnish a 
small amount of friction. When the knob is 
turned, the continuous driving tape d, gradu¬ 
ated in degrees of bearing, moves and carries 
the stylus e with it. Stops were provided to limit 
the back-and-forth motion of the stylus. The 
index j indicates on the tape the bearing being 
traced by the stylus e. 

The principal components of the modified re¬ 
corder are (1) the called-bearing stylus e with 
a knob for driving it; (2) the actual projector¬ 
bearing stylus b with mechanical connection to 
its motor drive; and (3) a clock-motor mech¬ 
anism for moving the paper. 

The string-driven stylus b is operated through 
a 5CT synchro from the maintenance of true 
bearing [MTB] system on a 1:1 basis (in 
degrees). A 110-v, 60-c, two-phase driving 
motor is geared to give a maximum speed of 
approximately 10x360 degrees per minute, thus 
providing an available speed twice as great as 
ever required. 

The synchro / and the driving motor g with 


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RECOMMENDATIONS FOR FUTURE DESIGN 


173 


its amplifier are mounted on a plate attached 
to the recorder case. Removable cover plates 
provide access to this equipment. 

The synchro is geared to a shaft to which 
the driving motor is also geared through a fric¬ 
tion clutch h. This clutch is a safety device to 





SLOTTED DISK 
ACTUAL BEARING STYLUS 
MANUAL CONTROL KNOB 
CONTINUOUS DRIVING TAPE 
CALLED BEARING STYLUS 
SYNCHRO 

SYNCHRO DRIVING MOTOR 
FRICTION CLUTCH 
DISK WITH PIN 
INDEX 


Figure 10. Cut-away diagram of OBR, showing 
modifications in original recorder. 


prevent stalling of the driving motor when the 
string-driven stylus reaches the stop at one end 
or the other of its travel. The shaft terminates 
in a disk i with a pin projecting from its face 
near the periphery. When the plate on which 
synchro and driving motor are mounted is 
fastened in place on the recorder, this pin in 
disk i enters the slot in disk a, coupling the 
string-driven stylus to its driving mechanism. 

In order that the string-driven stylus may be 
adjusted to have a 45-degree range on either 
side of a central zero in each of the four bearing 
quadrants, a ring attached to the synchro is 
marked off into eight equal divisions: N, NE, 
E, SE, S, SW, W, and NW. The top cover plate 
of the OBR may be swung back on hinges to 
allow the synchro to be turned manually from 


quadrant to quadrant as the bearings change. 


136 RECOMMENDATIONS FOR FUTURE 
DESIGN 

The operational bearing recorder [OBR] was 
built in a short time, largely from material 
already at hand, in order to permit a quick test 
of the usefulness of this type of instrument. 
Experience showed that the following modifica¬ 
tions would contribute greatly to the ease of 
operation and general adaptability of any simi¬ 
lar instrument that might be contemplated. 

1. The single true-bearing stylus should be 
replaced by four or more properly marked styli 
placed 90 scale degrees apart on a tape. The use 
of multiple styli would eliminate the necessity 
for manually setting the synchro head as well 
as the need for travel stops and safety friction 
clutch. 

2. The manual driving system of the called- 
bearing stylus should be designed so as to 
eliminate the necessity for resetting the stylus 
with respect to the tape scale when changing 
quadrants. 

3. Traces of the true-bearing stylus should 
be made distinguishable from those of the 
called-bearing stylus, either by color or by the 
type of lines drawn. 

4. The styli should be so designed that the 
instrumental error, which in the present re¬ 
corder shows as a time lag of approximately 
2 sec between actual bearing and called-bearing 
traces, would be as small as possible. 

5. Any new recorder should be designed to 
carry a wider record paper than was used in the 
experimental model. A chart graduated to 120 
degrees rather than to the present 90 degrees 
would prevent the traces from continually run¬ 
ning off the edge of the recording paper. 

6. A more satisfactory record paper should 
replace the red wax-coated chart used in the 
Barber-Coleman recorder, since the wax re¬ 
moved by the styli piles up and interferes with 
the operation of the driving mechanism. It is 
also true that the present records are easily 
marred and cannot be blueprinted. Chemical 
range recorder paper may be used if the traces 


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174 


MISCELLANEOUS TRAINERS AND DEMONSTRATORS 


of the styli are not to be distinguished from 
each other by the use of different colors. 

7. Provision should be made for a larger 
plate or flat surface under the record paper so 
that notations may be made on the chart as the 
traces are being drawn. 

8. The OBR described in this report was 
built for use with MTB. For operation with 
equipment that does not furnish true projector 
bearing and where only relative bearing and 
gyro-synchro circuits are available, the CT 
synchro-controlled servo drive should be re¬ 
placed by a differential synchro with servo fol¬ 
lower. The latter type of drive is to be pre¬ 
ferred, in any case, since with it the bearing 
recorder may be applied to all types of sound 
gear, whether equipped with MTB or not. 


The British bearing recorder AS407 seems to 
be readily adaptable for use as an operational 
bearing recorder. With it, the above-listed re¬ 
quirements for improvement over the present 
OBR should be adequately met. 

137 CONCLUSION 

The operational bearing recorder was satis¬ 
factory for its intended purpose. It did not 
come into common usage as a training device 
because it was too complicated and because it 
required resetting of the synchro head and 
stylus each time the quadrant of operations 
changed. In addition, the recorder required the 
full attention of an operator to set in manually 
the called bearing. 


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Chapter 14 

TRAINERS FOR SUBMARINE SONAR OPERATORS 


T rainers developed for the use of student 
submarine sonar operators closely paralleled 
those of the antisubmarine warfare [ASW] 
sonar program. Thus, the primary listening 
teacher, which was similar to the primary 
bearing teacher, was a simple device designed 
for elementary instruction and for rapid quan¬ 
tity production. The advanced listening teacher, 
completed in the summer of 1944, provided 
training under more realistic conditions but 
suffered from the same disadvantage as the 
advanced bearing teacher, namely, that it re¬ 
quired the instructor to devote his entire atten¬ 
tion to one student at a time. 

References to microfilmed material on these 
early listening teachers will be found in the 
bibliography for this chapter. They are not 
covered here because they were eventually 
superseded by the more efficient group listen¬ 
ing teacher. In this device the problem generator 
of the advanced listening teacher was adapted 
for use with ten or more operator stations 
simultaneously under the direction of one in¬ 
structor. 

This chapter includes first a discussion of 
the sound recognition group trainer [SRGT], 
which is a direct adaptation of the echo recog¬ 
nition group trainer [ERGT] used in ASW 
sonar operator training. Then follows an ac¬ 
count of the range indicator trainer [RIT], 
which is an adjunct of the sound recognition 
group trainer. 

The noise-level monitor trainer [NLMT], 
which is next described, simulates the condi¬ 
tions of using the noise-level monitor at sea. 
It is followed by a brief reference, illustrated 
by a photograph, to the torpedo detection modi¬ 
fication [TDM] trainer. However, no detailed 
laboratory report was prepared for the TDM 
trainer. 

The group listening teacher [GLT], and the 
monitoring equipment developed for use with 
sonar gear aboard Navy training barges, are 
the most complex of the trainers in this group, 
and are covered last. 



Figure 1 . Sound recognition group trainer, 
general arrangement of equipment. 

Sound Recognition Group Trainer 

The sound recognition group trainer, de¬ 
veloped by UCDWR, is a device for reproducing 
at each of 20 student stations the sounds from 
a phonograph recording played at an instruc¬ 
tor’s position, and for registering a permanent 
record of each student’s judgment of ivhat he 
hears. The student registers his judgment by 
pressing one of the buttons at the student sta¬ 
tion. For a variety of realistic operating con¬ 
ditions, the output of the phonograph pickup 
can be reproduced through either standard JP- 
type or WCA-type receiver or through a self- 
contained amplifier with a frequency response 
flat within 1 db from 50 c to 10 kc. 

i4.i INTRODUCTION 

Prior to the development of the sound recog¬ 
nition group trainer, the Navy’s sound recog¬ 
nition training program was handicapped by 
the fact that existing teaching equipment re¬ 
quired the instructor to devote his entire atten¬ 
tion to one student at a time. In 1944, there 
was an increasingly urgent need to train sonar 
operators in groups. Existing equipment pro¬ 
vided training under realistic conditions, but 
it could not train operators fast enough to sup- 


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175 






176 


TRAINERS FOR SUBMARINE SONAR OPERATORS 


ply the demand. The problem of training oper¬ 
ators in groups was therefore undertaken. 

The general arrangement of the units in the 
SRGT is shown in Figure 1, the equipment at 
the instructor’s position in Figure 2, a student’s 



Figure 2. Instructor’s position in SRGT. 


station in Figure 3, and a block diagram of the 
electric circuits in Figure 4. As indicated in 
these figures, most of the equipment is mounted 
in a control console cabinet, which is the in¬ 
structor’s station. The 20 student stations are 
arranged in three rows, so that the students 
face the instructor. 

The recorded sounds are classified and di¬ 
vided into groups, each of which gives the stu¬ 
dent some practice in some problem of target 
identification. Before the instructor plays a 
recording, a code is arranged for the class. For 
instance, the sound of own-ship’s screws may 
be represented by the number 1 and for con¬ 
venience, the No. 1 pushbutton may be labeled 
“screws,” as shown in Figure 3. The student 
listens to the sound recordings over the head¬ 
phones and records his judgment by pushing 
one of the buttons on the student station panel. 
When he pushes the button, the corresponding 
number appears in facsimile on the paper of 
one of two monitor recorders at the instructor’s 
station. By looking at the printed record of the 
students’ decisions, the instructor is able to 
coach the students, and easily grade their per¬ 
formance. 

Instructor’s Station 

The phonograph turntable and pickup ac¬ 


commodate records up to 16 in. in diameter, 
either 78 or 331/3 rpm. The various possible 
operating conditions are chosen by means of 
the circuit selector switch and the amplifier 
selector switch, both on the panel of the “flat” 
amplifier unit. When the circuit selector switch 
is in the normal position, the output of the 
phonograph amplifier is fed directly to the 
input of one of three units, depending on the 
position of the amplifier selector switch. The 
flat amplifier (response uniform within 1 db 
from 50 c to 10 kc), mounted in the console 
cabinet, is used when the amplifier selector 
switch is in the flat position, while either a 
standard JP-type or a standard WCA-type re¬ 
ceiver is used when the switch is in the J or W 
positions respectively. The output of the am¬ 
plifier used is fed through suitable impedance¬ 
matching circuits to headphones both at the 
students’ stations and at the instructor’s posi¬ 
tion. The signal level at the headphone circuits 
is indicated by a decibel meter mounted on the 
panel of the flat amplifier (some of the re¬ 
cordings include a 1,000-c reference tone for 
adjusting the overall level). The instructor may 



Figure 3. Student station in SRGT. 

talk to the students by means of a microphone 
provided at the control console. 

When the circuit selector switch is in the 70-c 
high pass, in the keying, or in coding posi¬ 
tion, a 70-c high-pass filter is connected be¬ 
tween the phonograph pickup and the input 


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INTRODUCTION 


177 


of whichever amplifier is used. This filter ren¬ 
ders inaudible to the students any 70-c or 40-c 
signal tones included in the recording. The 


range indicator trainer, described in the next 
section. When the switch is in the coding posi¬ 
tion, the 40-c signals from the phonograph 



Figure 4. Block diagram of SRGT. 


equipment is used with the circuit selector 
switch in the 70-c high-pass position when it is 
desired to listen to recordings containing such 
low-frequency signals without actually em¬ 
ploying them for any other purpose. The switch 
is placed in the keying position when the re¬ 
cordings contain 70-c signals for operating the 


record are used to actuate the monitor re¬ 
corders. 

Student Stations 

The equipment at each student’s station con¬ 
sists of a pair of headphones, an assembly of 
70 pushbuttons, and an auxiliary manually 


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178 


TRAINERS FOR SUBMARINE SONAR OPERATORS 


operated key. Sixty-seven of the pushbuttons 
are numbered 1 to 67 inclusive; the remaining 
three are labeled “??,” “Yes/’ and “No.” (Some 
of the pushbuttons bear additional designations 
appropriate to the training material being 
used.) When one of the numbered nonlocking 
pushbuttons is depressed, that number appears 
in facsimile on the paper of one of the two 
monitor recorders at the instructor’s position. 



Figure 5. Scanning transmitter in SRGT. 


The symbols f, X, and 0 respectively are repro¬ 
duced when the pushbuttons marked “??,” 
“Yes,” and “No” are depressed. The facsimile 
reproduction is repeated approximately 50 
times per minute as long as the pushbutton 
remains depressed. Responses from students’ 
stations 1 to 10 inclusive appear on monitor 
recorder No. 1, whereas stations 11 to 20 in¬ 
clusive are accommodated by monitor recorder 
No. 2. The instructor is provided with an iden¬ 
tical set of pushbuttons, and his responses are 
reproduced simultaneously on both monitor re¬ 
corders. When the manually operated auxiliary 
key at a student station (or at the instructor’s 
position) is closed, a solid black line is repro¬ 
duced on the paper of the monitor recorder in 
the column normally occupied by the second 
digit. In addition, the circuits are arranged to 
provide a rapid means of checking the re¬ 
sponses of the students against the correct an¬ 
swers which the instructor places on the 
monitor recorder papers by employing his own 
pushbuttons for second-digit blanking. Sup¬ 
pose, for example, that the instructor depresses 
pushbutton 45 and at the same time closes the 
auxiliary keying circuit (by means of his aux¬ 
iliary key or a toggle switch) at the instruc¬ 


tor’s position. The digit 4 followed by a black 
line will then appear in the columns of monitor 
recorder paper assigned to the instructor. If a 
student now depresses his pushbutton 45, the 
digit 4 followed by a black line will appear in 
the column assigned to that student’s station; 
if the student depresses 35, a 3 followed by a 
black line will appear; and if he depresses any 
number not containing the digit 5, both digits 
will be reproduced in the normal manner. 

Facsimile System 

The principles of operation of the facsimile 
system employed in the SRGT are described 
with the aid of figures showing, respectively, 
the scanning transmitter, the monitor recorder, 
and a simplified schematic of the electric cir¬ 
cuits. The scanning transmitter, Figure 5, con¬ 
sists essentially of (1) a metal scanning disk 
driven at 50 rpm by a single-phase motor and 
(2) a block of insulating material, or template, 
containing metal inserts shaped like the num¬ 
bers and symbols to be reproduced in facsimile. 
The scanning disk carries a spiral array of 21 
spring-loaded pins which complete an electric 
circuit between the scanning disk and the metal 
inserts. The contact pins are so arranged that 
during one revolution of the scanning disk each 



Figure 6. Monitor recorder for SRGT. 

metal insert is crossed by 11 pins, i.e., the elec¬ 
tric circuit is opened and closed eleven times. 
The scanning of the inserts is done from the 
inside of the spiral outward (from the bottom 


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INTRODUCTION 


179 


to the top of each number or symbol). Since 
the metal inserts have equal angular spacings 
and the contact pins move at a uniform rate, 
the length of time the electric circuit between 
a pin and an insert is complete (and hence the 
length of line reproduced on the monitor re¬ 
corder paper) depends on the shape of the 
letter or symbol. The order of scanning is such 
that the corresponding one of the 11 lines for 
each number or symbol is reproduced on the 
monitor recorder paper at the same time. 

Monitor Recorders 

The monitor recorders (Figure 6) are tac¬ 
tical sound range recorders modified for this 


PUSH-BUTTON assembly 
AT INSTRUCTOR'S POSITION 



NO.1 NO. 2 


Figure 7. Functional schematic of facsimile 
system of SRGT. 


particular application. The recorder driving 
motor moves the paper 7*/2 in. per minute 
and, through a set of gears and a mechani¬ 
cal linkage, causes the stylus assembly to move 
horizontally back and forth across the paper 
twelve times while the scanning disk makes one 
revolution. The reciprocating movement of the 
stylus assembly and the rotation of the scan¬ 
ning disk are synchronized so that the styli 


start their horizontal traverse just before a pin 
on the scanning disk makes contact with a 
metal insert. When the electric circuit to a par¬ 
ticular stylus is completed by depressing the 
appropriate student’s or instructor’s pushbut¬ 
ton, one trace will appear on the recorder paper 
for each traverse of the stylus, and a complete 
number or symbol will be reproduced during 
the time for 11 traversals. The time required 
for these traversals is 11 / L2 of that required for 
one revolution of the scanning disk; during the 
remaining y 12 revolution, all pins ride on the 
insulating material of the template, and thus a 
space is provided between the successive fac¬ 
simile reproductions on the monitor recorder 
paper. 

The arrangements for completing the elec¬ 
tric circuits to the various styli by means of 
the pushbuttons is shown in Figure 7 (only the 
circuits associated with the instructor’s push¬ 
buttons 46 and 64 are given in detail). This 
schematic shows how the desired metal inserts 
are connected to the stylus associated with the 
first or second digit by means of the pushbut¬ 
tons. The circuits from the students’ stations 
are similar, with the exception that only one 
pair of styli are associated with each station. 
When the instructor’s auxiliary key is closed, 
the stylus associated with the second digit is 
energized continually and a solid line appears 
on the monitor recorder paper. If the instructor 
depresses simultaneously his auxiliary key and 
one of his numbered pushbuttons, the second 
digit of that number will be blacked out wher¬ 
ever it would normally appear (depending upon 
which pushbuttons are depressed at the stu¬ 
dents’ stations). 

A complete description of power and ampli¬ 
fier circuits and interconnections together with 
operating and maintenance instructions may be 
found in the microfilmed reports on the SRGT 
listed in the bibliography. 

Phonograph Recordings 

The phonograph recordings prepared for use 
with the SRGT provide drills in order of in¬ 
creasing difficulty, and test turn-count estima¬ 
tion, faint contact detection, target identifica¬ 
tion, and other auditory discriminations. 


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180 


TRAINERS FOR SUBMARINE SONAR OPERATORS 


WHITE-ON-BLACK INDEX UNE 

DIAL WITH PLEXI- APPEARS IN 



ON BOTTOM 


Figure 8. Range indicator trainer, front panel. 

Range Indicator Ttainer 

The range indicator trainer [ RIT\, developed 
by UCDWR, is an eyilarged range indicator of 
the type found on WCA submarine sonar equip¬ 
ment. It is used ivith the sound recognition 
group trainer [ SRGT ] to train students in 
single-ping range reading and in estimating 
ranges from secondary echoes, as well as in 
estimating the echo-ranging interval of an 
enemy ship. It has a round dial, calibrated from 
0 to 5,000 yd, and a short index line of light 
that moves clockwise over a path adjacent to 
the dial scale. For single-ping ranging exercises, 
the RIT can be automatically synchronized with 
the SRGT disk-recorded selections, so that the 
index line lights up and begins to rotate from 0 
at the time of each ping transmission. After one 
revolution, the index line disappears, and the 
mechanism of the RIT stops until the cycle is 
begun again at the next ping transmission. 

The front panel of the range indicator 
trainer, shown in Figure 8, looks like an en¬ 
larged version of Type WCA range indicator. 

The primary purpose of the RIT is to permit 
realistic training in single-ping range reading. 
At the same time, synchronized operation per¬ 
mits the instructor to focus the attention of his 


class on a particular sound. He points to the 
dial at the range of the sound in question, and 
the students concentrate on what they hear as 
the index line passes the indicated range. 

By setting the RIT to run continuously and 
independently of the recorded selections, fur¬ 
ther uses can be made of the device. The stu¬ 
dents can use the indicator as a timer for turn 
counts by converting the indicated yards to sec¬ 
onds (800 yd equal 1 sec). Besides being con¬ 
venient in the classroom, this timing method is 
important because it can be used aboard ship. 
The techniques of ranging by secondary echoes 
and of determining echo-ranging interval can 
also be practiced when the RIT is set to operate 
continuously. These techniques are briefly de¬ 
scribed as follows: Under certain sound condi¬ 
tions, secondary echoes from enemy pinging are 
prominent enough to allow the sonarman to 
estimate range by observing the difference in 
indicator readings between the time of a ping 
and that of a ping echo from the enemy ship. 
Whenever enemy pinging is heard, the interval 
of echo ranging can be determined by observing 
the difference in indicator readings between 
successive pings. 

142 GENERAL DESCRIPTION 

Figure 9 shows the RIT with the dial and the 
front part of the cabinet removed. The me¬ 
chanical-electrical assembly is fastened to the 
center of the rear panel. The cable running 
from the assembly to the bottom of the cabinet 
connects (from left to right) to the 115-volt a-c 
plug, the power switch, the fuse, the pilot light, 
the run-keying switch, and the connector to the 
pulse line from the SRGT. With power and 
pulse line connections made, the device is put 
into operation by snapping the power switch to 
on and by setting the other switch to run if con¬ 
tinuous operation is desired, or to keying if the 
indicator is to be synchronized with the SRGT 
recorded selections. 

If the RIT is placed in a long classroom, it 
may be necessary to substitute larger dial num¬ 
bers than those marked on the dial, using paste- 
overs on the Plexiglas dial cover. This will be 
especially necessary if there is any troublesome 
glare. The white ring immediately inside the 


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GENERAL DESCRIPTION 


181 


dial scale is translucent, so that the index line, 
which is projected from an optical system 
behind the dial, shows through. 

Mechanical Assembly. Figure 10 is a close-up 
of the mechanical-electrical assembly of the 
range indicator trainer. Mounted on the frame 
is the lens-arm assembly that carries the index¬ 
line optical system. Two sets of ball bearings 


Telechron motor, which is mounted at the top 
of the frame. Current for the 6-volt lamp enters 
the lens-arm assembly through a contact button 
at the inside end of the shaft. An insulated wire, 
which passes through the hollow shaft, connects 
the contact button to the lamp. The current re¬ 
turns through the metal parts of the lens-arm 
assembly and passes to the frame through two 


HOLE FOR 
HANGING 


115 V A-C PLUG 


POWER SWITCH 



CABLE 


MECHANICAL- 

ELECTRICAL 

ASSEMBLY 


FUSE 


SPRING LATCH 


CONNECTOR TO SRGT 
PULSE LINE 


RUN-KEYING SWITCH 


PILOT LIGHT 



Figure 9. Range indicator trainer with front panel removed. 


hold the lens-arm assembly shaft perpendicular 
to the front of the frame and in. down from 
the top. Rigidly clamped to the shaft is the lens 
arm, which carries at its extremity a 6-volt 
lamp, a cylindrical lens, and a light shield. The 
latter three elements are arranged to focus a 
sharp index line on the back of the dial. A 120- 
tooth driven gear, also clamped rigidly to the 
shaft, engages a 19-tooth pinion of a 60-rpm 


carbon brushes in contact with the side of the 
driven gear. 

A cam is fixed to the rest of the lens-arm as¬ 
sembly by a ^-in. rod, which is perpendicular 
to the shaft and is displaced by 180 degrees 
from the lens arm. The cam serves two pur¬ 
poses : it operates a microswitch when the 
index line reaches 0, and it counterbalances the 
lens arm. 


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182 


TRAINERS FOR SUBMARINE SONAR OPERATORS 


On the left side of the frame are mounted 
(from top to bottom) a 6x5 tube, two Leach 
Type 1127 relays, and a 10-10 /rfd condenser. 
A single-pole, double-throw microswitch is 
mounted on the front of the frame about two 
inches from the bottom. An octal socket for con¬ 
nections to external circuits is near the bottom 


CYLINDRICAL LENS (6 V LAMP BEHIND LENS) 



LENS-ARM ASS’Y 
SHAFT 


10-10/lf 

CONDENSER 


Figure 10. Mechanical-electrical assembly of 
the range indicator trainer. 


of the right side of the frame. A 115/6.3-volt 
transformer is mounted inside the frame on the 
left side. 

Electric Circuit. Figure 11 shows the electric 
circuit for the range indicator trainer. One side 
of the 115-volt power line runs directly from 
J-703 to terminal 3 of P-701. The other side of 
the power line first goes through fuse F-701 and 
power switch S-701 and then connects to termi¬ 
nal 4 of P-701. Terminals 3 and 4 of J-701 sup¬ 
ply 115-volt alternating current to (1) the 
primary of transformer T-701 and (2) the 
charging circuit of condenser C-702, which in¬ 
cludes tube V-701 and resistor R-701. The sec¬ 
ondary of transformer T-701 supplies 6.3 volt 


alternating current to (1) pilot lamp 1-702 
through the J-701 to P-701 terminals 7 and 8, 
(2) index-line lamp 1-701 through the sliding 
contacts, the contact button, and the contacts of 
relay K-701, and (3) the heater of tube V-701. 

When switch S-702 is set at run, terminals 
3 and 5 of J-701 supply 115-volt alternating cur¬ 
rent to (1) motor B-701 and (2) relay K-701 
through condenser C-701. These connections 
cause the index line to rotate continuously and 
the index-line lamp (1-701) to remain on. 

When switch S-702 is set at keying, the volt¬ 
age on terminal 5 (the motor and index-line 
lamp control terminal) of J-701 depends upon 
the connections to terminal 6 of J-701. Terminal 
6 connects to the contacts of the pulse relay 


2 AMP POWER 

PULSE 115V FUSE ON OFF PILOT 

J-702 J-703 F=70l S-701 S-702 1-702 



Figure 11. Electrical schematic of the range 
indicator trainer. 

K-702 and to the microswitch. For ease of dis¬ 
cussion, the normally closed contacts of the 
relay and the microswitch have been labeled 
“A,” and the normally open contacts have been 
labeled “B.” Table 1 analyzes the switching con- 


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GENERAL DESCRIPTION 


183 


ditions in the order of their occurrence. The 
function of C-701 is to keep the d-c braking cur¬ 
rent from going through the coil of K-701. Dur¬ 


ing the periods when the motor is at rest and 
C-702 is charging, the resistor R-701 limits the 
pulsating direct current through V-701. 


Table 1 


Initial status of 
index line 

Closed contacts 

K-702 

microswitch Remarks 

At rest at 0. 1-701 
extinguished. 

A B 

No voltage on coil of 
K-702. Cam holds micro¬ 
switch at B. Low value of 
direct current is fed to 
motor through R-701 and 
V-701. No change in status. 

At rest at 0. 1-701 
extinguished. 

B B 

Voltage pulse on coil of 
K-702. Cam holds micro¬ 
switch at B. 115-volt 

alternatingcurrent through 
K-702 B contacts, starts 
motor, lights 1-701. C-702 
charges. 

In motion near 0. 
1-701 lit. 

B A 

Voltage pulse continues on 
coil of K-702. Cam release 
microswitch to A. 115- 
volt alternating current 
through both K-702 B 
contacts and microswitch. 
A contact runs motor, 
lights 1-701. C-702 con¬ 

tinues to charge. 


Initial status of 
index line 

Closed contacts 

K-702 

microswitch Remarks 

In motion around 

A A 

Voltage pulse has ended, 

dial. 1-701 lit. 


causing A contacts to close, 
B contacts to open on 
K-702. 115-volt alternat¬ 
ing current through micro¬ 
switch. A contact runs 
motor, lights 1-701. C-702 
continues to charge. 

Approaching 0. 

A B 

No voltage on coil of 

1-701 lit. 


K-702. Cam closes micro¬ 
switch B contact. 115-volt 
alternating current cut off 
from motor and 1-701 con¬ 
trol relay (K-701). Charge 
of C-702 surges through 
K-702 and microswitch 
contacts and through 
motor to give braking 
action. Motor stops. 1-701 
is extinguished. Cycle is 
completed. 



Figure 12. Noise level monitor trainer. 

Noise Level Monitor Trainer 

The noise level monitor [ NLM ] trainer, developed by CUDWR-NLL, introduces into a stand¬ 
ard noise level monitor sea-recorded background and auxiliary noise to familiarize the student 
with various types of NLM readings and their correct interpretation. An NLM attached to a 
JP amplifier, a control unit, a loudspeaker, and two playbacks are used. The noise recordings 
utilized in this equipment were obtained through submarine-mounted NLM hydrophones. 


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184 


TRAINERS FOR SUBMARINE SONAR OPERATORS 


The noise-level monitor trainer equipment is 
shown in Figure 12. It operates on 110-volt d-c 
power supply. The JP amplifier with NLM 
chassis mounted, is a duplicate of a shipboard 
installation, except for a few minor modifica¬ 
tions in the amplifier to adapt it for use with 
the trainer. Chief among these is the discon- 


AUXILIARIES OUTPUT TO 

INPUT JP 



Figure 13. NLM trainer control unit. 


nection of the positive d-c lead from the magnet¬ 
izing switch to protect the trainer control unit 
from accidental discharge of the magnetizing 
current. 

The control unit, shown in Figure 13, con¬ 
sists essentially of two sets of variable attenua¬ 
tors, one set for the background channel, the 
other set for the auxiliaries channel. Recorded 
background noise is fed into the background 
channel, and auxiliary noise from various sub¬ 
marine auxiliaries in order of increasing diffi¬ 
culty into the auxiliaries channel. The combined 
output of any pair of attenuators (for example, 
No. 1 background and No. 1 auxiliaries) repre¬ 
sents the output of one NLM hydrophone. There 
is a realistic addition of levels. Thus if an 
auxiliary measuring 23 db by itself is mixed 
with a background measuring 20 db, the NLM 
reading will be about 25 db. Figure 14 is a 
schematic showing the electric circuits. 

The output of the control unit passes through 
a shielded cable to the NLM chassis mounted on 



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GENERAL DESCRIPTION 


185 



Table 2. 

NLM trainer 

control-unit settings. 


Form 

Record number 

Auxiliaries 

measured 

Control-unit settings 

Desired NLM 
readings* 


background auxiliaries 

attenuators attenuators 




12 3 4 

1 2 3 4 1 

2 

3 

4 

Form 1. NLM calibration meas¬ 

4 

Water noise only background 

7 

11 

9 

6 

urements (individual auxiliaries) 

1 

Forward gyro set reg. power 

- - - - 25 

16 

10 

8 


1 

QB sound training motor generator 

- - - - 36 

14 

11 

8 


1 

No. 2 air conditioning 

- - - - 10 

19 

11 

7 


2 

Refrigeration plant 

- - - - 9 

16 

11 

7 


2 

Hull ventilation blower supply 

- - - - 8 

11 

19 

6 


2 

Aft. gyro setting regulator, power 

- - - - 12 

14 

10 

27 

Form 2. Calibration (overall) 

3 

Rigged for silent running, 40 rpm - - - - 

37 

25 

26 

20 


3 

Normalsubmergedoperation,40rpm — - — - 

36 

37 

32 

34 

Form 3. Daily check (overall) 

3 

Rigged for silent running, 40 rpm - - - - 

37 

27 

27 

21 


3 

Normalsubmergedoperation,40rpm - - - 

37 

38 

33 

34 

Form 1. NLM patrol measure¬ 

3 

Minimum evasive machinery, 40 





ments (suspected auxiliaries) 


rpm - - - - 

15 

20 

22 

20 


1 

No. 2 air conditioning plant 

- - 16 

23 

22 

20 


2 

Refrigeration plant 

16 

37 

22 

20 


* These are plausible relative levels. The actual readings may vary 2 or 3 db either way. This is probably caused by variations in the amplifier, pickup, 
phonograph records, or power supply. It means that the instructor cannot tell from the attenuator settings exactly what the meter readings will be. 
He must observe the meter while the students get the readings. 


a JP amplifier. From here the signal is fed 
through the amplifier of a playback to a loud¬ 
speaker, so the students can read the meter and 
hear the sounds as well. The controls of the 
NLM are used just as in normal operation. 

A separate cable runs from the control unit 
to the JP receptacle, providing a nonvariable 
noise level through the auxiliaries channel, when 
the NLM selector switch is turned to the JP 
position. 

The two small switches at the left of the 
panel provide means for matching the input 
impedances of the two channels to the im¬ 
pedances of the pickups on the two playbacks. 
The off position turns off the signal in that par¬ 
ticular channel, even if a record is playing. The 
magnetic position, used with magnetic pickup, 
provides an impedance of 5,000 to 8,000. The 
crystal position, used with crystal pickup, pro¬ 
vides an impedance of 100,000 ohms. 

Any type of crystal or magnetic pickups may 
be used, but since individual playbacks vary 
considerably, it is necessary to calibrate the 
control unit of each trainer before putting it 
into operation in the classroom, so that the in¬ 
structor will know what attenuator settings to 
use in the drill. Table 2 shows a complete NLM 
drill, 1 including the NLM readings desired in 
each case, and blanks for the control unit set¬ 
tings necessary to get those particular readings. 


The recordings used with the trainer are 
16-in. disks, playing at 33 Ys rpm, of sounds re¬ 
ceived through four NLM hydrophones mounted 
on a submarine’s pressure hull. The auxiliary 
set simulates submarine auxiliaries under dif¬ 
ferent conditions, such as the submarine lying 
on the bottom (background noise only), mini¬ 
mum evasive, rigged for silent running, and 
normal submerged. In the more complex drills, 
high noise levels are reproduced, and the pro¬ 
cedure for testing individual auxiliaries to 
locate the noisy one requiring repair can be 
illustrated. 


Torpedo Detection Modification Trainer 

The torpedo detection modification [ TDM~\ 
trainer, is an adaptation of the QFL range re¬ 
corder teacher. Five TDM bearing recorders 
have been substituted for the range recorders. 
This adaptation was given the Navy designa¬ 
tion QFM. The QFL type of amplifier and con¬ 
trol unit, playback, and loudspeaker are used in 
the QFM, but the recordings are of torpedo 
sounds instead of echoes and reverberation. 
These simulated torpedo sounds produce char¬ 
acteristic traces on the bearing recorders, and 
at the same time are heard through the loud¬ 
speaker. TDM was developed by CUDWR-NLL. 


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186 


TRAINERS FOR SUBMARINE SONAR OPERATORS 



Figure 15. The TDM trainer. 


PROJECT 
INDICATOR PANEL 


REO TARGET BEARING BLUE TARGET BEARING 

REPEATER UNIT REPEATER UNIT 



Figure 16. Group listening teacher, instructor’s 
position. Note: “Project Indicator Panel” should 
read “Projector Indicator Panel.” 


Group Listening Teacher 

The group listening teacher [ GLT], de¬ 
veloped by UCDWR, is a device which realis¬ 
tically simulates the principal sounds heard by 
submarine sonar operators during important 
tactical situations, coordinates these sounds 
into three problems, each involving two targets 
and own-ship’s interference, and then applies 
them to five standard WCA-type sonar equip¬ 
ments enclosed in separate sound-treated 
booths. Interchangeable motor-driven cams 
control the variables of each problem. Ten 


operators receive training simultaneously (JK 
and QB operators at each equipment), and one 
instructor at a central console is able to monitor 
the performance of all ten operators continu¬ 
ously. It is possible also to incorporate eight 
JP and four WEB equipments into the trainer. 

The group listening teacher was an outgrowth 
of the advanced listening teacher [ALT], which 
provided training for only one submarine sonar 
operator at a time. It is essentially an extension 
of the principles of the ALT automatic problem 
generator to affect ten or more student operator 
stations simultaneously. The variables of each 
problem are controlled by a set of motor-driven 
cams, and the shifting from one problem to 
another is accomplished by changing to a dif¬ 
ferent set of cams. The two targets involved in 
each of the three problems are designated “red” 
and “blue.” Own-ship’s noise as well as a 
variety of water conditions and propeller sounds 
may be simulated, and pinging by one of the 
enemy targets may be injected into the prob¬ 
lem by the instructor at will. Any one of the QB 
operators, according to the instructor’s choice, 
may obtain single-ping ranges on one of the 
targets. An intercommunicating system is used 
for two-way conversation between the instruc¬ 
tor and the students, and for monitoring the 
students, either individually or collectively. 


14 3 GENERAL DESCRIPTION 

The description which follows deals only 
with the WCA portion of the group listening 
teacher, Model CXKG (formerly designated 
Model I, WCA). Each of the five WCA equip¬ 
ments in this portion of the trainer is installed 
in a separate soundproof booth, and the student 
can manipulate the controls in exactly the same 
way as under actual operating conditions. Prob¬ 
lem information from the instructor’s control 
cabinet is transferred to each WCA stack 
through a search unit mounted above the booth. 

Switches for controlling the training prob¬ 
lem and the instruments for monitoring the 
students’ performance are mounted on the front 
panels of the control cabinet, as shown in Fig- 


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GENERAL DESCRIPTION 


187 


ure 16. These controls and their principal func¬ 
tions are described below. 

Red Target-Bearing Repeater Unit 

A problem selector switch is used for select¬ 
ing one of the three problems to be used (see 
Figure 17). A three-position toggle switch con¬ 
trols the operation of the motor which drives 
the problem generating cams. When this switch 
is in the right-hand position, the problem pro- 


ure of the angular position of the camshaft). 
A standard bearing repeater arrangement in¬ 
dicates the true and relative bearing of the 
simulated red target. An indicator, calibrated 
in 100-yd steps from 0 to 5,000 yd, shows the 
approximate range of the red target. 

Blue Target-Bearing Repeater Unit 

A standard bearing repeater arrangement 
indicates the true and relative bearing of the 


RED TARGET " BUG" — 


POWER 


PROBLEM SELECTION 
CONTROLS 


PROBLEM CONTROL 
RESET-OFF- RUN 

ELAPSED TIME*- 

INDICATOR 



j—1-1402 
L-S-140 


€ 


I- 1405 
S- 14 03 
I- 1404 


_M —1402 


I FOOT 


M-I40I 

RED TARGET RANGE 


Figure 17. Red target bearing repeater unit. 


ceeds at a rate normal to the simulated tactical 
situation. When this switch is in the left-hand 
position, the camshaft is made to turn in the 
reverse direction at approximately ten times 
normal speed, thus facilitating the repetition 
of any part of a problem or the starting of a 
problem at any point. The cams are stopped 
when this switch is in the center position, thus 
holding the target range and bearing fixed while 
all simulated sounds are produced in the regu¬ 
lar manner. An indicator, calibrated in ^-min¬ 
ute steps from 0 to 20 minutes, shows the time 
elapsed since the start of the problem (a meas- 


simulated blue target (Figure 18). An indica¬ 
tor, calibrated in 100-yd steps from 0 to 5,000 
yd, shows the approximate range of the blue 
target. A three-position key switch and a set of 
pushbutton switches control an intercommuni¬ 
cating system between the instructor and the 
students’ booths. By depressing the proper 
pushbutton, the instructor may hold a two-way 
conversation with any one of the ten students 
or with all simultaneously. When the key switch 
is in the “listen receivers” position, the in¬ 
structor hears the same sounds that the student 
hears and also hears the students’ oral reports. 


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188 


TRAINERS FOR SUBMARINE SONAR OPERATORS 


Projector Indicator Panel 

This panel contains ten indicators calibrated 
in 15-degree steps from 0 to 360 degrees, which 
show the relative bearing of the simulated JK 
and QB projectors associated with the WCA 
equipments (Figure 16). 


ground noise applied to the receivers in the 
WCA equipments. Three noise levels are avail¬ 
able, corresponding to good, medium, and bad 
water conditions. 

A functional block diagram of the problem¬ 
generating features of the Model CXKG is 
given in Figure 19. Mechanical linkages are 


BLUE TARGET "BUG” 



S-1602 


INTER- COM 
‘CONTROLS 


PHONE JACK 


601 

BLUE TARGET RANGE 


Figure 18 . Blue target bearing repeater unit. 


Target Noise Control Panel (Figure 16) 

A single-ping QB switch is used to determine 
to which one of the five QB operators the simu¬ 
lated single-ping reverberation and echo are 
available. An enemy ping frequency switch 
enables selection of either 17 or 27 kc as the 
enemy echo-ranging frequency. An enemy ping 
interval control enables setting the enemy echo¬ 
ranging keying interval at any value between 
500 and 3,500 yd. Two screw selector switches, 
one for the red target and one for the blue 
target, each permit the independent choice of 
any of five simulated screw sounds. A torpedo 
explosion switch is used to initiate the simulated 
explosion. A torpedo problem toggle switch in 
the on position allows simulated torpedo sounds 
to reach the students. A water-conditions switch 
determines the intensity of the simulated back- 


shown as dashed lines, electrical as solid. The 
variables of a problem (speed, range, bearing, 
and doppler) are controlled by a set of ten cams, 
shown at the bottom of the figure, driven by 
constant-speed motor B-1201. This motor also 
drives a position transmitter R-1210 associ¬ 
ated with an indicator M-1402 (on the panel 
of the red target-bearing repeater unit) which 
provides a measure of the angular position of 
the cams, i.e., of the portion of the problem 
being generated. This indicator enables the in¬ 
structor conveniently to set the cams to any 
predetermined position called for by the in¬ 
structional program. Similar position trans¬ 
mitters R-1203 and R-1209, driven by the blue 
and red target range cams, provide indications 
of the approximate range of each target to the 
instructor’s position. 


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GENERAL DESCRIPTION 


189 


Screw Sounds. Own-screw sounds are gen¬ 
erated by means of a glass disk rotating be¬ 
tween a light source and a photoelectric cell 
PE-1202. Opaque segments of suitable size, 
spacing, and density have been deposited on 
this disk, so that the intensity of the light beam, 
and hence the output of the photoelectric cell, 
is varied in accordance with the desired screw 
sounds. The revolutions per minute of the 
simulated screws depend on the speed of rota¬ 
tion of the glass disk. This disk is driven by 
the output shaft of a conventional type of me¬ 
chanical speed changer. The constant-speed 
disk of the speed changer is driven by motor 
B-1204, while the output roller is moved across 
the face of the constant-speed disk by the own- 
speed cam. Thus the speed of rotation of the 
glass disk, and hence the revolutions per min¬ 
ute of the simulated own screws, is made to 
vary with own speed as the problem progresses. 
The volume level, or intensity, of the simulated 
screw sounds depends on the intensity of the 
light source. Power for the source is obtained 
from transformer T-504 through resistor 
R-1204. The latter is also varied by the own- 
speed cam, and provides the desired variation 
of intensity of own-screw sounds with speed. 

Screw sounds for the red and blue targets are 
generated in the same manner as described in 
the previous paragraph. In order that a variety 
of targets may be available for training pur¬ 
poses, each of the glass disks in the target 
screw-sounds generators has five sets of 
opaque segments, each set simulating a dif¬ 
ferent type of target and having a separate 
light source. The choice of simulated screw 
sounds to be used is made by means of the 
screw selector red target and screw selector 
blue target switches S-1503 and S-1504 on the 
target noise control panel at the instructor’s 
position. These switches have off positions so 
that a problem involving only one target can 
be run when desired. Resistors R-1201 and 
R-1206, driven respectively by the blue target 
and red target speed cams, provide for the 
variation of intensity of target screw sounds 
with target speed as the problem progresses 
(intensity proportional to speed up to 12 knots; 
constant thereafter). The glass disks are driven 
through speed changers as previously described 


so that the revolutions per minute of the simu¬ 
lated screws vary with target speed. 

Random Noise. The output of each photo¬ 
electric cell, PE-1201, PE-1202, and PE-1203, 
is amplified by a separate screw-sounds ampli¬ 
fier and then fed to a mixer tube where it is 
combined with random noise. The spectrum of 
this random noise, generated by a gas tube, 
extends to at least 35 kc, hence the output of 
each mixer is a wide-band supersonic signal of 
random noise modulated with the screw char¬ 
acteristics as determined by the interrupted 
light beam in the screw-sounds generator. The 
own-screw-sounds mixer output is fed directly 
to the search units, whereas the red target and 
blue target mixer outputs are fed to the search 
units through resistors R-1207 and R-1202 
respectively. These resistors are controlled by 
the red target and blue target range cams and 
cause the intensity of the target signals to vary 
with range. 

Part of the output of the random-noise gen¬ 
erator is fed through water-conditions switch 
S-1506 on the panel of the target noise control 
panel and resistor R-1205 to the inputs of both 
the JK and QB receivers in each WCA equip¬ 
ment to simulate nondirectional background 
and water noise. Switch S-1506 has three posi¬ 
tions, these representing bad, medium, and 
good water conditions. Resistor R-1205 is driven 
by the own-speed cam and causes the intensity 
of the water noise to vary with own speed. 

Bearing Information. The own-bearing cam 
drives synchro generator G-1201, which then 
supplies true-bearing information to gyro-com¬ 
pass repeaters in the red target-bearing re¬ 
peater unit and the blue target-bearing repeater 
unit at the instructor’s position, and to the QB 
and JK gyro-compass repeaters in each of the 
five WCA equipments. The relative bearing of 
each target is obtained from the output of a 
differential, the inputs being from the own¬ 
bearing cam and one of the target-bearing cams. 
These differentials drive synchro generators 
G-1202 and G-1203, which supply, respectively, 
blue target and red target relative bearing in¬ 
formation to the five search units. 

All information, both own and target, that 
is a function of the projector bearing is sup¬ 
plied to each WCA equipment through its own 


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190 


TRAINERS FOR SUBMARINE SONAR OPERATORS 



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Figure 19. Functional block diagram of group listening teacher 












































































































































































GENERAL DESCRIPTION 


191 


search unit. Own-screw sounds are applied to 
two fixed coils, while the red and blue target 
signals are fed to separate movable coils the 
physical positions of which are controlled with 
respect to the fixed coils by the relative bearing 
synchros G-1801 and G-1802. The combined 
signals fed to the WCA receiver inputs are ob¬ 
tained from series-connected movable coils, 
separate pickup coils being used for each target. 
The pickup coils are moved in relation to the 
target and to the fixed coils by means of d-c 
training motors which are controlled by the 
projector training circuits in the WCA equip¬ 
ment. Thus, for example, when the JK operator 
moves his training hand lever, the JK training 
motor in the search unit will rotate the JK 
pickup coils; the intensity of his own screw 
sounds and of the target signals applied to the 
JK receiver will then depend on the position of 
the pickup coils with respect to the fixed coils 
(JK projector bearing) and the target coils. By 
proper mechanical and electrical design, the 
overall signal pickup characteristics of the 
search unit are made to simulate those of actual 
projectors in a realistic manner. Each training 
motor drives (1) a position transmitter through 
which the projector bearing is reproduced on 
the projector indicator panel at the instructor’s 
position and (2) a synchro-generator which 
transmits the projector bearing to a ring dial, 
or “bug,” in the WCA equipment. 

Echo-Ranging Signals. Provision is made for 
the simulation of echo-ranging signals by the 
red target on a frequency of 17 or 27 kc. The 
choice of frequency is made by means of the 
enemy ping frequency switch S-1502 on the 
target-noise control panel. The output of the 
oscillator which produces the enemy echo-rang¬ 
ing signals is fed to one grid of a mixer tube, 
the tube normally being biased to the cutoff 
point. The reduction of the bias to a value which 
will permit the mixer to produce an output 
signal is controlled by a gas-tube switch. When 
S-1502 is in the off position, the plate circuit to 
the gas tube is open and the mixer is cut off. 
The plate circuit is closed when S-1502 is in 
either the 17 kc or 27 kc position, and the gas- 
tube switch then intermittently removes the 
bias from the mixer at a rate determined by 
the setting of the enemy ping interval control 


R-1506. By means of this control, mounted on 
the target-noise control panel, any keying in¬ 
terval between 500 and 8,500 yd may be simu¬ 
lated. The cutoff bias is gradually restored (and 
the output signal intensity gradually decreased) 
by means of a resistance-capacity delay net¬ 
work, thus simulating the delay of an echo¬ 
ranging signal with time. The intensity varia¬ 
tion of the reverberations is simulated by 
varying the conductance of the mixer; the po¬ 
tential of one grid of the mixer is varied in a 
random manner with a d-c voltage obtained by 
rectifying random noise. The mixer output, 
then, is a realistic enemy echo-ranging signal 
and is fed to the search unit, along with the red 
target screw sounds, through resistor R-1207, 
which provides for intensity variation with 
range. 

Any one of the five QB operators may range 
on the red target, the choice being made by 
means of the single ping QB switch S-1501 on 
the target noise control panel at the instructor’s 
position. This switch connects both the range 
indicator keying circuit and the local oscillator 
in the QB receiver to a mixer which is normally 
biased to cutoff. The mixer is also provided with 
a 60-kc signal from an oscillator (shown in the 
upper right-hand portion of Figure 19) and 
with random d-c voltage. When the range indi¬ 
cator keying circuit is closed, the cutoff bias is 
overcome and a mixer output which simulates 
realistic single-ping reverberations is obtained 
at the frequency to which the QB receiver is 
tuned. Since, in practical cases, the reverbera¬ 
tions heard are independent of the projector 
bearing, this signal is fed directly to the QB 
receiver input (through a section of S-1501). 
A resistance-capacity delay network gradually 
restores the mixer bias to cutoff in the manner 
described in the previous paragraph. 

The range indicator keying circuit and the 
local oscillator in the QB receiver are also con¬ 
nected from S-1501 to another mixer from 
which the single-ping echo is obtained. This 
mixer is provided with a signal whose fre¬ 
quency is 60 kc plus the amount of doppler con¬ 
sistent with the problem; the frequency of the 
oscillator is controlled by the doppler cam over 
a range of ±300 c. The mixer output, therefore, 
is at the frequency to which the QB receiver is 


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192 


TRAINERS FOR SUBMARINE SONAR OPERATORS 


tuned, plus the appropriate amount of doppler. 
The mixer is normally biased to cutoff. When 
the range indicator keying circuit is closed, a 
delay period is started which is made propor¬ 
tional to the red target range by R-1208 (driven 
by the red target range cam). At the end of 
this period, the mixer cutoff bias is momen¬ 
tarily overcome, and an echo signal is pro¬ 
duced at the mixer output. This signal is fed 
with the other red target signals to the search 
unit through R-1207, since the intensity of the 
received echo is a function both of target range 
and of projector bearing. 

Torpedo Noise. If a particular problem calls 
for the firing of a torpedo, switch S-1207 will 
be operated at the appropriate time by the tor¬ 
pedo cam. The blue target screw sounds are 
then replaced by the simulated torpedo sounds 
(generated electronically) through the torpedo 



Figure 20. Barge monitoring equipment. 


problem switch S-1505 on the target-noise con¬ 
trol panel at the instructor’s position. By open¬ 
ing this switch, the torpedo sounds can be 
eliminated when desired. The torpedo sounds 
are fed to the search units through R-1202, 
which provides intensity variation with range. 
Explosion of the torpedo may be simulated by 
closing explosion switch S-1507 on the target- 
noise control panel. The explosion sounds are as¬ 
sumed to be nondirectional, hence are fed di¬ 
rectly to the inputs of the JK and QB receivers. 

Power Supply. Direct current of 110 volts is 
necessary to supply filament heating power and 
plate voltage throughout the system, but all 
other components are operated by 115-volt al¬ 
ternating current. Detailed information on the 
operation of the circuits may be found in the 
preliminary instruction manual listed in the 
bibliography for this chapter. 



Figure 21. Instructor’s console, barge monitor¬ 
ing equipment. 


Barge Monitoring Equipment 

Barge monitoring equipment, developed by CUDWR-NLL, is a device which enables one 
instructor to monitor four JP equipments installed in a Navy training barge. The monitor con¬ 
sists of the instructor’s console, a main control box, and four students’ control boxes (one on 
each JP amplifier). The console includes repeater dials folloiving the pelorus topside, and a talk- 
back system which permits the instructor to communicate with the operators individually or all 
four at once. The insUmctor may also pick up the output of any JP amplifier to check the 
signal being received by the student. A hand telephone set and E call circuit connect the console to 
the pelorus watch topside. The main control box carries the intercom amplifier and the station 
selector relays. The students’ control boxes simulate the opera tor’s control of the NL-119 JP inter¬ 
com system. 


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Chapter 15 

TRAINERS AND DEMONSTRATORS FOR SUBMARINE OFFICERS 



Figure 1 . Modified Mark I conning officer attack teacher as installed at the U.S. Navy Submarine Base, 
New London, Connecticut. 


Conning Officer Attack Teacher Modification 

The conning officer attack teacher modification, developed by CUDWR-NLL, is an extensive 
redesign of the Mark I attack teacher used in the trainmg of submarine conning officers and their 
associated personnel. The original model consisted essentially of a conning tower and periscope 
associated with a single manually controlled target ship model mounted on a target-bearing car. 
The modifications include the provision of multiple targets, new and variable lighting effects, re¬ 
peater units in the conning tower and classroom, simulated underwater sounds, and radar pat¬ 
terns. The problem presented is controlled from a Mark I torpedo data computer, which likewise 
underwent some modifications. 


E xcept for some minor alterations, the Mark 
I attack teacher, originally constructed in 
1920, had not been modernized. Interim im¬ 
provements in sonar gear, the introduction of 
radar, and the overall demands of submarine 
warfare in World War II made a redesign im¬ 
perative. 

As modernized, the conning officer attack 
teacher makes it possible to reproduce in the 
classroom the conditions of a submarine attack 
frotn the instant the enemy ship (or ships) is 


sighted until the torpedoes are fired. It is thus 
of great assistance in the training of prospec¬ 
tive submarine commanding officers, approach 
officers, and fire control parties. 

As shown in Figure 1, the equipment is in¬ 
stalled in a classroom with two decks. Training 
sessions take place on the lower deck, where a 
submarine conning tower rotated by a power 
drive is the student’s station during a practice 
run. A repeater unit and plotting table on this 
deck enable the instructor to follow the course 


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193 





























194 


TRAINERS AND DEMONSTRATORS FOR SUBMARINE OFFICERS 


of the problem and to analyze the trainee’s 
performance. 

The periscope of the conning tower is brought 
through the floor of the upper deck, where it 
may be focused on a target convoy made up of 
miniature ships mounted on a target bearing 
car similar to the spokes of a wheel. The target 
bearing car is driven on a track toward or 
away from the periscope to simulate closing or 
opening range. The miniature ships are also 
maneuverable in relation to one another. Light 
conditions can be varied during the course of a 


various screen ships; (4) the relative angular 
position of the screen ships with respect to the 
target; (5) the position in azimuth of the 
simulated conning tower and hence the relative 
bearing of the target with respect to the sub¬ 
marine; (6) the apparent sound range and 
bearing of the target ship and the variation of 
background water noise caused by changes in 
own-ship’s speed. 

By using this equipment, a student is able to 
observe an enemy ship or convoy through a 
standard periscope. He can then maneuver his 



Figure 2. Target bearing car and sky canopy. 


problem from brilliant sunlight to any degree 
of darkness desired, including red sunrise and 
red sunset. 

The torpedo data computer which generates 
the problem, the auxiliary control cabinet, and 
the sound injector are also located on the upper 
deck. The generated data are picked up through 
synchro units and are used to control (1) the 
motion of the target bearing car on the track 
and hence the simulated range; (2) the bearing 
and angle-on-the-bow of the central target ship; 
(3) the bearing and angle-on-the-bow of the 


submarine through the approach and attack 
phases of the problem to attain a favorable 
firing position. Actual conditions are simulated 
in the speed and relative bearing of the target 
ship or ships, speed and course of the attacking 
submarine, and the changing range caused by 
the interaction of these factors. 

151 DESCRIPTION 

Target Bearing Car. The target bearing car, 
shown in Figure 2, carries all target and screen 


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DESCRIPTION 


195 


ships of the simulated enemy convoy. Provision 
is made for mounting as many as seven auxili¬ 
ary ships on arms supported by the carrier 
plate, one roving destroyer on a special arm 



Figure 3. Track for target bearing car and peri¬ 
scope support table. 


likewise supported by the carrier plate, and one 
central target ship on a shaft independent of 
the carrier plate. All seven ships may be maneu¬ 
vered together as screen ships, or up to four 
of them may be used as auxiliary target ships. 
Should it be considered desirable to use all 
seven arms for screen ships and yet have auxili¬ 
ary target ships, four new arms may be made 
and mounted in sockets and brackets provided 
on the carrier plate. 

Rotation of the plate carrying the central 
target ship is servo-controlled from the signals 
given out by the angle-on-the-bow synchro in 
the torpedo data computer. By the use of 
synchro differentials and followers actuated 
from the torpedo data computer, the screen and 
auxiliary ships (including the four extra 
models, if these are added) will automatically 
maintain the same angle on the bow as the 
center target ship or, by the operation of a 
switch, maintain automatically a 000-degree 
angle on the bow independent of the center tar¬ 
get. If it is desired, a lead or lag may be intro¬ 
duced into their relative positions through the 
auxiliary control cabinet. They can also be 


made to start and maneuver for position ahead 
of the target ship as it changes course. The 
roving destroyer is separately maneuvered from 
the auxiliary control cabinet. 

The target bearing car travels along a 75-ft 
track directly in front of the periscope (see 
Figure 3). (Some installations may use a 
37 14 -ft track with proportionally smaller ship 
models.) The car’s distance and speed of travel 
are determined by the range and closing rate of 
the submarine and target ship and are con¬ 
trolled by the range synchro-generator in the 
torpedo data computer, which feeds through a 
control transformer and a servo-amplifier to 
the driving motor of the car. The car travels on 
four wheels, two of which, on one track, are 
grooved and two, on the other track, wide 
flanged. This keeps the car aligned with the 
axis of the track and provides lateral stability. 

Submarine Course and Speed Repeater. In 
order that the approach officer may know the 
course and speed of his own boat at all times, 
an own-course and speed repeater (Figure 4) 
is mounted in the conning tower. This consists 
of two 5-in. dials mounted in a small cabinet 
and driven by two standard 5F synchro fol¬ 
lowers. These are actuated by own-course and 



Figure 4. Own-course and speed repeater in 
conning tower. 


own-speed synchro generators in the torpedo 
data computer and maintain the same readings 
on the repeater dials as those on the correspond¬ 
ing dials of the torpedo data computer. The re- 


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196 


TRAINERS AND DEMONSTRATORS FOR SUBMARINE OFFICERS 


peater dials are engraved, filled with luminous 
paint, and illuminated by lamps in the cabinet. 
This system of illumination is employed 
throughout the trainer wherever dials are in¬ 
stalled. 

Instructor’s Repeater. An instructor’s re¬ 
peater is provided to relay certain information 
from the torpedo data computer to the instruc¬ 
tor in the classroom on the lower deck. It con¬ 
sists of a small cabinet in which are mounted 
four dials showing relative bearing, angle-on- 
the-bow, target speed, and range at all times 
during the course of the problem. The dials in 
this repeater are driven by four 5F synchro 



Figure 5. Sound injector. 

followers actuated by corresponding synchro¬ 
generators in the torpedo data computer. 

Auxiliary Control Cabinet. The auxiliary con¬ 
trol cabinet provides means for controlling the 
angle-on-the-bow of the screen ships or their 
rotation around the center target manually or 
automatically. It also provides control of the 
roving destroyer and the lighting effects inside 
the sky canopy. The left-hand crank controls 
the rotation of the carrier plate and the degree 
of rotation can be read on the left dial on top 
of the cabinet. The right-hand crank controls 
the course of the screen ships relative to the 
center target with the right-hand dial showing 
the number of degrees the course has been 
changed. The two lower knobs control the 
Variacs which produce the various lighting 
effects. Across the top of the cabinet is a bank 
of switches which control lights and mechan¬ 
isms for either automatic or manual operation. 


A switch is also provided for switching in a 
second Mark I torpedo data computer (if avail¬ 
able) in case of failure of the first, and a Variac 
for controlling the speed of the roving destroyer. 

Power Drive for Conning Tower. The power 
drive for the conning tower is located under 
the periscope support table. It operates on a 
signal from the relative bearing synchro in the 
torpedo data computer and rotates the conning 
tower as directed. Power is obtained through 
the use of an amplifier, an amplidyne, and a 
d-c motor. This motor drives a small spur gear 
which, in turn, drives the large gear on the con¬ 
ning tower shaft. Electrically, the directing 
signal from the relative bearing synchro is fed 
into a synchro-control transformer, which then 
drives the amplidyne amplifier. The signal from 
the amplifier supplies the control fields of a 
motor generator which in turn supplies arma¬ 
ture current for the main amplidyne motor. 
When there is no signal from the relative bear¬ 
ing synchro, the generator has no control field 
current and hence no output. Under this con¬ 
dition the rotor of the amplidyne motor is 
stationary. 

Periscope Support Table. At the point where 
the periscope comes through the deck, a grille- 
enclosed steel table is located. This table sup¬ 
ports the periscope and houses the amplidyne 
power unit for driving the conning tower. Since 
it is of simple construction and may have to be 
altered to fit individual installations, it is con¬ 
structed “on location.” 

Sky Canopy and Lighting Effects. In order 
more nearly to simulate actual attack condi¬ 
tions, a skyline background and variable con¬ 
ditions of light and dark are provided about the 
enemy convoy. This is accomplished through 
the use of a large plywood canopy, shown in 
Figure 2. The canopy is open at the front in 
order not to interfere with periscope vision and 
is painted with clouds and blue sky at the rear 
as a background for the target ships. A bank 
of lights at the front and another at the rear 
of the canopy are controlled by Variacs in the 
auxiliary control cabinet to provide different 
lighting effects. 

Sound Injector. In order to inject into the 
conning tower sonar gear sounds which would 
simulate realistically the problem presented by 


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DESCRIPTION 


197 


the motion of the target ship model, an elec¬ 
tronic sound injector, shown in Figure 5, was 
developed. It introduces into WCA or JP-1 
sonar equipment sounds closely resembling 
those of a target ship and also simulated water 
noise. The artificial echo representing the tar¬ 
get ship can be “placed” at a range exactly 
corresponding with the model ship’s position 
on the target bearing car in relation to the 
periscope. Further arbitrary and automatic ad¬ 
justments, including provision for correct bear¬ 
ing indication via the echo, make it possible to 
produce a highly realistic sound situation. 



Target Answer Block on Film,Vi$ible Through 
Eyepiece ot Low Power With Verticoi Sweep 
Up, Contains ONI Code, Ship Nome, Angle- 
On-Bow, and 


F«lm Retaining 
Index Letter 
Film Drum-— 
index Number 
Torget Ring 


Ship Roll Amplitude 


ond High Power Adjustment 


Stadimeter Opening- 


Focus Adjustment 


How to Use Recognition 

Charts’*- 

{on bock of panel) 


Recognition Charts 


CONTROL PANEL 
Target Knob 
Illumination aff-on 
Sea Intensity 
Sky Intensity 
Roll Motor off-on 
Roll Frequency Control 


to Use The 
Periscope Trainer" 


Figure 6. Overall view of periscope trainer, 
Mark III. 


Periscope Trainer 

The periscope trainer, developed by CTJDWR- 
NLL, is a device for the elementary training of 
officers in ship recognition, judgment of bear¬ 
ing and angle-on-the-bow, and estimation of 
range by telemeter or stadimeter. It is a mock- 
up of the lower part of a submarine periscope 
and its operation is essentially the same as that 
of a standard periscope. Replacing the top of 
the periscope, however, is a circular drum in 
ivhich are inserted film strips showing target 


ship images at various ranges and angles-on- 
the-bow. The images are back-illuminated by 
lamps contained in a housing which rotates 
with the periscope tube so that the illumination 
is always directly behind the field of view. The 
target drum is rotated by a hand control to 
change targets, or target positions. After 
identifying the target ship and estimating its 
angle-on-the-bow and range, the student can 
check his answers by tilting the vertical sweep 
in low power until an ansiver box above the 
ship image becomes visible. 

Three models of the periscope trainer were 
designed. The third and final model, designated 
the Mark III periscope trainer, is shown in 
Figure 6. The lower part of the trainer dupli¬ 
cates the ocular end of a Type II Kollmorgen 
Corporation periscope in which the usual pro¬ 
visions are made for focusing, training, and 
reading bearings. Although the periscope has 
been reduced in length, its operation and optical 
properties are essentially the same as those of 
a standard periscope. As the synthetic model is 
trained through 360 degrees, the upper lens 
sweeps through a continuous photographic view 
of the sea. Ships of various types, ranges, and 
angles-on-the-bow are included in the trans¬ 
parent film, illuminated from behind. Targets 
are moved so that correct perspective is main¬ 
tained for the supposed range. Own-ship’s roll, 
variable in amplitude and period, is simulated. 

Accompanying each trainer is a set of target 
ship films, consisting of 12 strips with 13 views 
on each strip. These cover 49 merchant vessels 
and 20 warships, all Japanese. Figure 7 is a 
contact print of a portion of film strip showing 
the answer boxes which, together with the rec¬ 
ognition charts and instructions posted near 
the controls, enable a student officer to practice 
on the trainer alone and check his performance. 


is.* DESCRIPTION 

The periscope trainer is an optical system 
contained in a three-part assembly which is 
made up of a periscope body tube, a periscope 
head casting, and a target ring at the top. This 
main assembly rotates in bearings attached to 


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198 


TRAINERS AND DEMONSTRATORS FOR SUBMARINE OFFICERS 


a support which is mounted on a wall bracket 
or table. 

Optical System. The optical system consists 
of a ray filter, eyepiece lens, eyepiece prism, 
telemeter scale, stadimeter lenses, special low- 
power objective, special high-power objective, 
upper prism, film drum, target film, heat ab¬ 
sorbent glass, diffusing screens, and lamps. A 
schematic diagram of the optical system is 
shown in Figure 8. 

Illumination. The lamp housing contains two 
110-volt, 25-watt, candelabra-base, tubular-type 
lamps, each 514 -in. long. These are controlled 


to this small and exact scale, a special fine¬ 
grained film is required (Eastman Kodak No. 
548). Special developing techniques were found 
necessary and were perfected by the producer, 
Kellogg and Bulkeley, in order to obtain the 
necessary gradation with the fine-grain re¬ 
solving power desired. 

The horizon on the film strips is continuous 
and is located approximately one-third the dis¬ 
tance from the bottom of the 4-in. printed por¬ 
tion of the film. The ships are so spaced that 
only one ship is in the field of view when the 
image is centered. The image of a merchant 


•; 



6 MFM 

KITURIN MARU 
80°P 2000 


7 MFM 
KATORI MARU 
85 ° S 3000 


6 MFM 

KOKURYU MARU 
1O0° P 3000 


16 M K F K M 
BANGKOK MA 
85° S 



Figure 7. Contact print of portion of film strip. 


by rheostats located on the side of the trainer. 
The horizontal arrangement of the lamps, one 
above and one below the horizon line, permits 
illumination of either the simulated sea or sky 
with varying intensities to represent various 
visibility conditions. 

Target Film.. The telemeter scale has 32 scale 
divisions. Since the field on the target at high 
power is % in. in diameter, one of the divisions 
on the telemeter scale will subtend 0.023 in. 
Ranges from 1,500 to 6,600 yd are covered by 
the film strips. From the range formula, a ship 
with a 100-ft mast will subtend one division at 
7,640 yd; therefore, the ship images will range 
in size from about % 4 -in. mast height to a 
maximum of 2*4 in. for extremely close range. 

In order to reproduce faithfully target images 


ship as seen through the periscope trainer in 
high power is shown in Figure 9. It should be 
realized that some detail is lost in the reproduc¬ 
tion of these prints from the positive trans¬ 
parency. 

The film strips are systematically arranged, 
films A, B, C, D, and E showing 49 Japanese 
merchant vessels at moderate ranges (1,500- 
4,000 yd) and angles-on-the-bow close to 90 
degrees (65 to 125 degrees). Films F and G 
show 20 Japanese warships at similar ranges 
and aspects. These views lend themselves to 
elementary training in identification and range 
determination. Films H, I, J, K, and L show 
the same ships at longer ranges (1,900-6,600 
yd) and include aspects which make recognition 
more difficult. 


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DESCRIPTION 


199 


The films associated with the Mark I and II 
trainers were different in a number of ways. 
They did not include the “answer box,” the 
most important change. Without this feature, 
self-training was extremely difficult. Six addi¬ 
tional film strips in the Mark I and II set at- 




AIR-SPACEO HIGH-POWER OBJECTIVE 
(NOT IN OPTICAL PATH WHEN 
VIEWING IN LOWER POWER) 

OPTICAL STOP 



tempted to portray convoys, but the simultane¬ 
ous viewing of several ships at different ranges 
was not realistically portrayed, and the in¬ 
tended training was not only ineffective but 
possibly harmful. These convoy films were 
therefore eliminated in the Mark III set. In the 
rearrangement of the films for the Mark III 


unit, instances of poor reproduction were elimi¬ 
nated and rephotographed, and additional views 
were included to give a more balanced distribu¬ 
tion of the various ships at different ranges and 
aspects. 

Undoubtedly, as further experience is gained 
and perhaps as training needs change, addi¬ 
tional or different film strips will be desired. 
These may readily be produced, since the pio¬ 
neering work in this rather unusual photo¬ 
graphic problem has been completed. 

Vertical Siveep and Simulated Ship Roll. The 
upper prism cell is pivoted and carries an ex¬ 
tended arm to which is attached a long con¬ 
necting rod. This rod is brought down through 
the periscope tube, and its lower end is pivoted 
to the center of an equalizing lever. One end of 
this equalizer is attached to an eccentric on a 
crank driven by a motor. The crank pin and the 
eccentric each have the same swing and the 
eccentric is rotatable through 180 degrees on 
the crank pin. Turning the eccentric on the 
crank pin permits continuously adjustable ship 
roll from zero to approximately 8 degrees list 



Figure 9. Image of merchant vessel with peri¬ 
scope in high power. 

or 16 degrees total roll. Markings on the eccen¬ 
tric permit setting to any desired roll. The 
other end of the equalizer is connected to the 
left-hand training grip through a pitman and 
a crank on the training grip shaft. The rotation 


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200 


TRAINERS AND DEMONSTRATORS FOR SUBMARINE OFFICERS 


of the motor-driven crank tilts the upper prism 
simulating ship roll, which may be compensated 
for by equal and opposite operation of the 
vertical-sweep control. The ship-roll amplitude 
dial rotates slowly in operation, but it can be 
conveniently adjusted in motion if so desired. 
A Variac control on the side of the trainer per¬ 
mits adjustment of the frequency of roll. Fig¬ 
ure 10 is a schematic of the electric system. 

Horizontal Training. Training or sweep in 
horizontal azimuth is the same as with a stand¬ 
ard periscope and is effected by rotating the 


observing position, the combination of three 
lenses combine to form a plain window. Opera¬ 
tion of the stadimeter knob displaces the two 
movable lens halves by means of gearing and a 
cam and at the same time rotates the stadimeter 
dial. When the lens halves are displaced, they 
become in effect two optical wedges which dis¬ 
place half of the rays from the objective up¬ 
ward and the other half downward. This results 
in two images, each of which is approximately 
half as brilliant as the combined image. Stops 
are provided on the stadimeter knob shaft which 


ROLL MOTOR 


ROLL FREQUENCY TARGET FILM 



entire periscope assembly by means of the train¬ 
ing handles. In order to require the student to 
use the periscope-training handles, the target 
ring can be rotated to any desired position by 
means of a dial which is located on the bearing 
support frame. This has the same effect as if 
the submarine had changed course and makes 
it necessary to train the periscope on the target 
again. 

Stadimeter. By means of a stadimeter, the 
water line of a vessel in one image can be 
brought into apparent contact with the mast¬ 
head as seen in the oth,er image. The amount of 
displacement necessary to effect this is trans¬ 
lated on the stadimeter dials to the range of 
the vessel as read against the estimated or 
known distance between masthead and water 
line. In the type of stadimeter provided with 
the periscope trainer, the images are displaced 
vertically only. The lenses used for the dual 
images are so constructed that in the zero, or 


limit the movement of the dial to approximately 
382 degrees. 

Ship Finder and Recognition Charts. As 
shown in Figure 6, a ship finder and set of 
recognition charts are attached to the trainer 
for instant use by the student. A sample chart 
is reproduced in Figure 11. The instructions 
for using the charts are posted on the back of 
the trainer. The charts give the student im¬ 
mediate access to the information necessary for 
identification and, once the ship’s name is 
known, mast and stack heights for ranging are 
also available. Length and tonnage are also 
shown, so that the student may check his esti¬ 
mates of these figures. The position of the 
charts is such that they may be used by the stu¬ 
dent himself, by a mate when teams of two 
work together, by the instructor, and even by 
a small group. It may be seen in the data associ¬ 
ated with the recognition charts that some of 
the heights and lengths differ slightly from 


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DESCRIPTION 


201 


HEAVY CRUISERS LIGHT CRUISERS 


To tell them apart-look at: 

I. Number or stocks. 

2 Appearance of bridge 

3 Extension of upper deck 
4. Location of mainmast 
5 Number of turrets. 


To tell them apart-look at-. 

1 Number of stacks 

2 Appearance of bridge. 
3. Location of catapults. 



Nachi Class Natori Class 



Atago Class (B) 



Mogami Class 



Tone Class 


CARRIER 



Shokaku Class 


Sh»p 

H«.gM 

From Water 

Height 

From Deck 

Lsnglh 

0v*fO» 

Tot'S 

F M 

MU 

Stock 

FM MM I Stock 

Aobo Class 

137 

148 

68 

108 

III 46 

679 

7,100 

Nachi Class 

118 

168 

75 

92 

142 

49 

744 

10,000 

Atago Class (A) 

134 

148 

72 

106 

129 

44 

748 

9,850 

Atago Class (B) 

123 

139 

72 

94 

no 

43 

746 

9,850 

Mogami Class 

113 

170 

76 

87 

144 

50 

727 

8,500 

Tons Class 

151 

136 

71 

125 

110 

49 

750 

12,000 










Shokoku Class 

112 


*98 

52 


*38 

931 

15,000 










Ssndai Class 

124 

108 

53 

105 

89 

34 

610 

5,195 

Noton Class 

146 

113 

58 

124 

88 

36 

607 

5,170 

Yubari 

104 

81 

50 

87 

64 

37 

532 



Soda* 


Figure 11. Sample recognition chart. 


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202 


TRAINERS AND DEMONSTRATORS FOR SUBMARINE OFFICERS 


similar data for the same ships shown in the 
ONI. The measurements shown were scaled 
from the models photographed when it was dis¬ 
covered that the models were not all exactly in 
proper scale proportion as compared to the 
ONI data. The differences are not serious but 
had to be recognized if the actual ranges shown 
were to be determined correctly by telemeter 
fill and stadimeter computation. 

Operating Instructions. In addition to the in¬ 
structions posted on the trainer itself, an in¬ 
struction and maintenance manual has been 
issued . 1 This manual contains a set of answer 
sheets for instructors to use in checking the 
students’ observations and in selecting the tar¬ 
gets, aspects, and ranges desired for training. 



Figure 12. Torpedo angle solver demonstrator. 


Torpedo Angle Solver Demonstrator 

The torpedo angle solver demonstrator, de¬ 
veloped by CUDWR-NLL, is an enlarged work¬ 


ing model of the Mark VIII torpedo angle 
solver designed to demonstrate its correct use 
to groups of student officers. Data scales have 
been enlarged photographically to two and one- 
half times normal size, and other parts have 
been reproduced to scale. 



Figure 13. Submarine barometer simulator, 

front view. 

The Submarine Barometer Simulator 

The submarine barometer simulator was de¬ 
signed by UCDWR as an adjunct to the sub¬ 
marine diving trainer (Askania trainer) to re¬ 
produce the operation of a standard submarine 
barometer ivhen the vessel is preparing to sub¬ 
merge. The main assembly is a modified Navy 
aneroid barometer. On a control panel are the 
pressure indicator off-on switch, the pressure 
indicator light, and the “diving alarm” push¬ 
button. Operation of the diving alarm push¬ 
button causes the barometer needle to indicate 
“normal pressure”; release causes indication 
of “pressure in the boat.” 

On board an actual submarine, the internal 
air pressure is increased slightly just before 
submergence to make sure that all openings to 
the outside atmosphere are closed. If pressure, 
as indicated by the barometer, fails to build up 
at this time, the diving officer is warned that 
diving is unsafe. Since simulation of this oper¬ 
ation was provided in the submarine diving 
(Askania) trainer, the submarine barometer 
simulator was designed as an adjunct to the 
trainer. 


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DESCRIPTION OF CIRCUIT 


203 


15 3 DESCRIPTION OF CIRCUIT 

The wiring diagram for the device is given 
in Figure 14. Operation is as follows. When the 



Figure 14. Electrical schematic for the barom¬ 
eter simulator. 


diving alarm pushbutton is actuated, the con¬ 
tacts of the Leach 1157 relay are opened. Open¬ 
ing of these contacts de-energizes the 33L15 
actuator and a spring restores the on-off con¬ 
tacts on the Ward Leonard mechanical time- 
delay relay to the off or starting position. The 
simulated barometer needle is also coupled to 
the rotating arm carrying the on-off contacts of 
this relay, and restoration of this arm to the 
off position moves the barometer needle to the 
normal pressure indication point. This may be 


manually set at any value (ordinarily 29.6 in. 
of mercury). Release of the diving alarm push¬ 
button restores the circuit through the Leach 
1157 relay if the pressure indicator switch is 
closed. The Telechron motor is energized and 
rotates the contact arm of the Ward Leonard 
relay. After a suitable time interval, which may 
be preset by means of an adjusting nut on the 
rear of the Ward Leonard relay, this rotation 
increases the barometer needle indicator by 
0.3 in. of mercury, thus indicating “pressure in 
the boat,” and also closing the on contact which 
lights the pressure indicator light. The Ward 
Leonard relay is so constructed that the Tele¬ 
chron motor winding is opened when the on 
contacts are closed. Operation of the diving 
alarm pushbutton restores the indicated pres¬ 
sure to normal, and the cycle is repeated. 

If no pressure indication is desired, the pres¬ 
sure indicator switch is left in the off position; 
and if a pressure indication is desired with 
more time delay than is mechanically set into 
the Ward Leonard time-delay relay, the pres¬ 
sure indicator switch may be operated at any 
time after the diving alarm pushbutton has 
been actuated. The mechanical delay time will 
then be added to whatever manual delay time 
is used. 


The Bathythermograph Simulator 

The bathythermograph simulator [TRS], de¬ 
veloped by UCDWR, is a device designed (1) to 
introduce automatically into the Askania diving 
trainer the changes in water density with depth 
caused by a specific temperature gradient and 
(2) to trace on the card of a submarine bathy¬ 
thermograph mockup the corresponding depth- 
temperature curve. Any desired depth-tempera¬ 
ture pattern may be recorded on a master card 
for reproduction on the card of the bathy¬ 
thermograph simulator. A movable light-spot, 
photocell combination automatically folloivs the 
master card pattern and thereby gives temper¬ 
ature indications which are transferred to the 
temperature recording element of the bathy¬ 
thermograph mockup and to the “ density” con¬ 
trol shaft of the Askania trainer. 


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204 


TRAINERS AND DEMONSTRATORS FOR SUBMARINE OFFICERS 



Figure 15. Control box, showing bathythermo¬ 
graph master card. 

154 OPERATION 

Figure 16 is an isometric assembly drawing 
showing how the simulator is incorporated in 
the trainer. 

To service the simulator, a representative 
assortment of BT cards was prepared, covering 
the principal depth-temperature patterns of in¬ 
terest in the training program. On the back of 
these cards the area on the right-hand side of 
the depth-temperature trace is painted dead 
black and the remaining area is left white. The 
card is mounted on glass with the unpainted 
side against the glass. One of these cards is 
inserted in the front panel of the control box, 
with the glass face outward, as shown in Fig¬ 
ures 15 and 17. 

A lamp mounted inside the control box 
focuses a light spot on the back of the card 
through a series of aligning prisms (Figure 
20) and a movable microscope objective. In 
operation, the light spot is made to straddle the 
boundary between the black and white parts of 
the card by means of a servo system, the posi¬ 
tioning of which is determined by the amount 
of light reflected back through the microscope 
and into a photocell. The microscope-photocell 
unit is mounted on a carriage which is free to 
move both vertically and horizontally, thus pro¬ 
viding freedom for the light spot to follow the 
black-white boundary. The vertical position of 
the carriage corresponds to the depth of the 


submarine in the ocean and the horizontal posi¬ 
tion to the temperature. 

The microscope-photocell unit is given ver¬ 
tical movement by a selsyn receiver which re¬ 
sponds to a selsyn transmitter connected to the 
depth shaft of the Askania trainer (Figure 
16). By this means, the position of the light 
spot on the card is made to agree vertically 
with the submarine depth, both as simulated by 
the trainer and as indicated by the depth lines 
printed on the BT card. 

The horizontal position of the light spot on 
the card is determined photoelectrically by the 
particular pattern recorded on the BT card 
inserted in the machine. The horizontal posi¬ 
tioning is effected by a servo-motor system 
which automatically drives the carriage on 
which the microscope-photocell unit is mounted 
toward the black-white boundary and which is 
satisfied only when the light spot straddles this 
boundary. The output motor of the servo sys¬ 
tem is also coupled to the density control shaft 
of the Askania trainer, so that for each hori¬ 
zontal position of the light spot on the card the 
appropriate water density is set into the 
trainer. Accordingly, as the submarine depth 
changes in response to orders from the subma¬ 
rine commander, the light spot moves vertically 
to the indicated submarine depth and is driven 
horizontally so as to follow the contours of the 
depth-temperature curve; in so doing a change 
in water density is effected which reacts in a 
realistic fashion on the behavior of the sub¬ 
marine simulated by the Askania trainer. 

A submarine BT is installed in a position 
convenient for the student diving officer. (An 
inside view is shown in Figure 18.) By means 
of selsyn receivers which respond to the depth 
and temperature selsyn transmitters already 
described, the mockup BT records the same 
trace as that shown on the master card inserted 
in the control box. 

155 DESCRIPTION 

Control Unit. The front panel of the control 
cabinet, shown in Figure 15, is fitted with a 
rectangular opening for the master BT card 
and slots into which the card is inserted. There 
are also a motor switch and line switch, each 


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DESCRIPTION 


205 


with pilot lights and motor current indicating 
d-c ammeter. Two screwdriver adjustments for 
the amplifier are placed under the name plate 
on the front panel. One of these controls the 
stability of the servo system and the other 
controls the ratio of the black to white portions 
of the card seen by the photocell at balance. 

Mounted on the base plate of the control 
cabinet are the amplifier and thyratron chassis, 
the holding magnet, the motor relay, the satur¬ 
able core transformer for the light-source 
voltage regulator, and the track assembly for 
the microscope-photocell unit (see Figure 17). 

Track Assembly. The track assembly consists 
of a stationary track secured to the control 
cabinet base plate and having two vertical 
ways; a vertically movable carriage fitted with 
rollers which travel up and down along the 
above ways; and a horizontally movable car¬ 


riage which moves on rollers fitted to the ver¬ 
tical carriage. All the tracks are of aluminum; 
the horizontal carriage is in one piece and the 
vertical carriage consists of a top and bottom 
plate joined together by two side brackets. One 
side bracket carries prism No. 2. Prism No. 1 
is fastened to the top of the stationary track. 
On the back of the stationary track is installed 
an idler gear which engages a rack mounted on 
the vertical carriage and through which ver¬ 
tical motion is imparted to the vertical carriage 
by the depth selsyn. On the horizontal car¬ 
riage are mounted prisms No. 2 and 3 
(Bausch & Lomb No. 31-90-92-014), the photo¬ 
cell (RCA922), and the microscope objective 
(Bausch & Lomb 10.25 mm, 0.40 215TL). 
Prism No. 3 is mounted slightly to one side, so 
that although it deflects the light beam through 
the microscope objective on to the card, part 



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206 


TRAINERS AND DEMONSTRATORS FOR SUBMARINE OFFICERS 


of the returning reflection passes the prism and 
enters the photocell. Two shielded cables lead 
from the photocell to the amplifier unit. They 
are clamped to the horizontal carriage and run 
through a bakelite block on the stationary track. 

Elevator Unit. The vertical position of the 
light spot on the master BT card corresponds 
to the simulated depth of the submarine in the 



Figure 17. Control box, interior view. 

Askania trainer. The depth selsyn (see Fig¬ 
ure 17), mounted behind the stationary track, 
imparts vertical movement to the vertical car¬ 
riage through a train of gears which engage 
the idler gear previously mentioned. The 5F 
depth selsyn receiver responds to a 5G depth 
selsyn transmitter, which in turn is driven by 
the depth shaft of the Askania trainer. To pre¬ 
vent the vertical carriage from dropping be¬ 
cause of its own weight when the power is off, 
a serrated disk is mounted on the selsyn; and a 
holding magnet operates, through a mechanical 
linkage, a detent that engages the serrated disk. 

Translator Unit. The horizontal position of 
the light spot corresponds to water tempera¬ 
tures as traced on the master BT card that is 
inserted in the front panel of the control cabi¬ 
net. The horizontal movement is controlled by 
the reaction of the photocell to the reflected 
light from the card in the following manner. If 
the light beam is directed against the white 
portion of the card, the photocell is strongly 
illuminated by the resulting reflection. As the 


beam moves across the boundary line between 
black and white, the illumination will lessen 
until it reaches a minimum, when the beam is 
focused entirely upon the black portion. This 
movement from white to black, or vice versa, 
thus produces a gradual transition in photocell 
output. This output is converted by the ampli¬ 
fier and thyratron units into voltages suitable 
for the reversible servo motor which turns the 
density control shaft on the Askania trainer. 
Connected to the motor is a selsyn transmitter 
to which the temperature selsyn in the control 
unit responds. (The temperature selsyn, a 5F 
synchro motor, is mounted behind the station¬ 
ary frame of the carriage assembly alongside 
the depth selsyn, as shown in Figure 19.) 
Through gears and a pulley unit the tempera¬ 
ture selsyn imparts horizontal movement to the 
photocell carriage. If the photocell has excita¬ 
tion corresponding to a black region on the 



Figure 18. Submarine bathythermograph mock- 
up, inside view. 

card, the motor will rotate in one direction 
whereas if the lens is opposite white, the re¬ 
verse rotation will result. Thus the loop through 
the photocell, amplifier and power supply, 
motor, selsyns, and the variable light-reflecting 
characteristics of the card comprise a servo or 


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DESCRIPTION 


207 


automatic control loop. The polarities of this 
loop are such that if the light spot is not on 
the boundary line between white and black it 
will move until this condition obtains, at which 
time the density control shaft on the trainer 
will have been turned until the density factor 
in the trainer corresponds to the temperature 
indicated on the card. 


bly is secured to a bracket bolted to the control- 
cabinet base plate. The lens unit is made from 
a Petzval-type motion-picture projector lens, 
2-in. focal length and f 16 aperture, with the 
Plazzi-Smith field corrector element removed. 

Since the photocell response is in proportion 
to quantity of light, it is important that the 
light source be kept constant. In order to do 


THYRATRON CHASSIS 



Figure 19. Servo system schematic. 


Lamp Assembly. The light source consists of 
a Mazda No. 1493 lamp mounted in an alumi¬ 
num radiator to dispel the heat and a lens unit 
mounted ahead of the lamp; the entire assem- 


this it is necessary to regulate the power sup¬ 
ply to the lamp to reduce the effect of varia¬ 
tions in line voltage. This is accomplished by 
means of a voltage regulator which consists of 


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208 


TRAINERS AND DEMONSTRATORS FOR SUBMARINE OFFICERS 


a saturable core transformer, a current mini¬ 
mizing condenser and a bias transformer. 

Amplifier and Thyratron Units. The com¬ 
bined function of these two units is to convert 
the signal from the photocell into the appropri¬ 
ate control for the motor unit which turns the 
density control shaft on the trainer, and which 
also, through the temperature selsyns, imparts 



- 


Figure 20. Motor unit for the bathythermo¬ 
graph simulator. 

horizontal movement to the photocell, thus com¬ 
pleting the servo system loop. This servo sys¬ 
tem is illustrated schematically in Figure 19. It 
operates as follows: 

1. The signal from the photocell is brought 
into the amplifier chassis by means of two 
shielded leads and develops a voltage across 
load resistors R x . Resistor R. 2 and condenser C x 
provide decoupling for the input shields. Volt¬ 
age divider R, furnishes the photocell with the 
proper operating potential and supplies bias for 
tube section 6SN7/2A and the photocell. The 
IR drop across resistance R 4 supplies voltage 
for the resistance tubes T x and T 2 which are 
connected in series, with the junction returning 
to the cathode of tube section 6SN7/2B. Tube 
T. a amplifies and applies to the grid of tube 
6SN7/2B the first time derivative of the signal 
from the photocell. This time derivative is gen¬ 
erated by condenser C 2 , resistor R ri , and control 
Its application to the grid is equivalent to 


applying viscous damping to the mechanical 
system. Its magnitude is adjusted by control R IX 
to a value slightly less than “critical,” the value 
at which all oscillation just disappears. The 
effective output resistances of transformers L, 
and L l ., which control the firing times of the 
thyratrons by changing their bias phases, is de¬ 
termined by the grid-to-cathode voltages of the 
tubes T x and T... The voltages are in turn deter¬ 
mined by the relative cathode potentials of 
tubes 6SN7/2A and 6SN7/2B. Control R, so 
adjusts the operating point of tube 6SN7/2B 
that transformers L, and L 2 give equal output 
resistances when the spot is stationary and 
when it is straddling the black-white boundary. 
Also located on the amplifier chassis is a d-c, 
voltage-regulated power supply for tubes 
6SN7/2A, 6SN7/2B, T x , T. 2 , and T,, 

2. One of two thyratrons on the thyratron 
chassis controls the current in the servo motor 
when running forward; the other controls it in 
reverse. The phase rotating network, composed 
of condenser C 5 and resistor R x0 in the primary 
of the thyratron bias transformer, controls the 
steady-state current passed by the thyratrons 
when transformers L x and L, represent equal 
resistances. Condenser C 4 and the effective re¬ 
sistance of transformer L, make up a phase- 
rotating network, in the secondary of the thyra¬ 
tron bias transformer, which controls the firing 
time and therefore the current passed by thyra¬ 
tron T x . Condenser C 3 , transformer L,, and thy¬ 
ratron T :> , operate in the same manner to pro¬ 
duce the opposite direction of motor rotation. 
When, as a result of a depth change, a change 
in temperature appears on the BT card, there 
are three voltage sources that act to change the 
effective resistances of transformers L x and L 2 . 
They are (1) the displacement component from 
photocell, (2) the velocity component from 
photocell produced by the differentiating net¬ 
work C 2 , R-, R, ; , and (3) a fixed component 
from control R These operate as previously 
described to drive the servo motor in such a 
direction that (1) and (2) are abolished, and 
balance is restored at the new temperature. 
Also mounted on the thyratron chassis are a 
filament transformer for the thyratrons, a time- 
delay relay to allow filaments to heat, and a 
bias transformer for the lamp regulator. 


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DESCRIPTION 


209 


Motor Unit. This unit, shown in Figure 20, 
is mounted beneath the control panel of the 
Askania trainer. A horizontal shaft running 
the length of the unit’s base plate rotates in two 
bearing blocks. The servo motor (Bodine Elec¬ 
tric Company, NSE 12 RH % hp), a reversible 
series-wound d-c motor, mounted vertically 
above the shaft near one end, turns a spur pin¬ 
ion which engages a split spur gear mounted on 
the shaft but free to turn on it. To prevent back¬ 
lash, a lash-lock device is fitted to the gear. 

The wedge is clamped to and transmits 
torque to one section of a friction clutch, the 
other section being attached to the shaft. The 
end of the shaft beneath the motor is threaded. 
A traveling nut on the threaded portion trips a 
limit switch at each end of its travel and stops 
the motor. Mechanical stops are also fitted 
which would slip the clutch if the limit switches 
failed to operate. This protection is necessary 
in order to prevent the density control shaft 
being turned too far. 

Near the middle of the horizontal &haft is a 
worm which engages a worm gear attached to a 
vertical shaft. This worm gear is fitted with a 
lash lock similar to the one on the spur gear. 
The vertical shaft was designed to drive the 
density control shaft of the Askania trainer. 
Each end is fitted with universal joint. When 
the motor unit is installed, a section of the 
control shaft is cut out and the vertical shaft 
mentioned above fitted into its place. Thus the 
servo motor turns the density control shaft by 
means of the spur gear, friction clutch, worm, 
and worm gear. On the opposite end of the 
horizontal shaft from the motor assembly the 
temperature selsyn transmitter is mounted, 
resting in a bracket bolted to the base plate, 
and attached to the horizontal shaft by means 
of a flexible coupling. This transmitter is a 5G 
synchro generator. 

Bathythermograph Mockup. This unit, shown 
in Figure 18, is similar in mechanical design 
to an actual submarine bathythermograph, but 
the depth and temperature are controlled by 
two selsyns which respond respectively to the 
depth and temperature selsyn transmitters con¬ 
nected to the Askania trainer. Thus the depth- 
temperature record traced on the card is a dupli¬ 
cate of the trace on the master card inserted in 


the control cabinet. The selsyns in this unit are 
1-F synchro motors. Through a train of gears 
the depth selsyn, mounted near the middle of 
the base plate, moves the rocker attached to 
the fiber box and Lucite window, holding the 
card in such a manner as to impart vertical 
movement to the card. This corresponds to the 
submarine’s depth. The temperature selsyn, 
mounted at the end of the base plate farthest 
from the card, moves, through gears, an indi¬ 
cator arm which extends over the assembly and 
to which is fastened a vertical arm holding a 
stylus which rests against the card. By this 
means horizontal movement corresponding to 
water temperature is imparted to the stylus. A 
lamp mounted behind the card illuminates it so 
that it can be read through the Lucite end panel 
of the box. 

Depth Selsyn Unit. This selsyn is fitted into 
a bracket, designed to be installed beneath the 
Askania trainer control panel. When it is so in¬ 
stalled, a pinion on the selsyn shaft engages a 
gear on the trainer depth shaft. The latter gear 
is a part of the standard trainer equipment. 
The selsyn is a 5G synchro generator, and the 
brass pinion, which engages the gear on the 
trainer, is fitted with a lash-lock device. 



Figure 21. Submarine bathythermograph class¬ 
room demonstrator, front view. 

Submarine Bathythermograph 
Classroom Demonstrator 

The submarine bathythermograph classroom 
demonstrator [ SBCD ], developed by UCDWR, 
is a standard submarine bathythermograph 
modified by the addition of manual depth and 


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210 


TRAINERS AND DEMONSTRATORS FOR SUBMARINE OFFICERS 


temperature controls and used to demonstrate 
the construction and operation of a bathy¬ 
thermograph. The depth control is a small 
sylphon bellows through which varying pres¬ 
sures can be exerted upon the pressure-sensi¬ 
tive element of the bathythermograph. The 
temperature control is a long column of liquid, 
bringing heat to the temperature Bourdon tube 
of the bathythermograph from an electric heat¬ 
ing unit. 

The submarine bathythermograph classroom 
demonstrator consists of a BT with its cabinet 
removed, as shown in the center of Figure 21; 
a bracket holding two 250-watt lamps of the 
type known as drying lamps, connected in 
parallel and facing a copper BT temperature 
tube about 75 ft long wound in pancake form 
on a spider; and a control panel. All these com¬ 
ponents are mounted on a base plate, as shown 
in the figure, with the card of the BT plainly 
visible to the class. 

Figure 22 shows the apparatus on the back 
of the control panel. The depth knob on the 
panel operates a copper sylphon bellows fast¬ 
ened to the back of the panel and connected to 
a pipe. The pipe in turn is connected to the 
Bourdon tube which actuates the depth move¬ 
ment of the BT stylus. The bellows, pipe, and 
tube are filled with castor oil, thus forming a 
hydraulic link by means of which the depth 
knob moves the card holder vertically. The 
temperature knob on the panel adjusts a vari¬ 
able autotransformer (a 5-amp, 110-volt, 60-c 
Variac), which controls the voltage supplied 
to the lamps. This voltage supply determines 
the volume of the liquid in the temperature 
tube, which in turn controls the horizontal 
movement of the BT stylus. There is also a 
rapid-change switch, which turns the lamps on 
or off independently of the Variac. It is used 
to obtain the maximum rate of temperature 
change. 

156 OPERATION 

The BT stylus moves horizontally in response 
to the expansion and contraction of the tem¬ 
perature Bourdon tube, in a manner similar to 
normal operation at sea, except that the tem¬ 


perature in the SBCD is controlled by the heat 
from the lamps. The closed capillary tube, 
wound on a spider and facing the lamps, as 
previously described, is connected to the tem¬ 
perature Bourdon tube, and the entire system 
is filled with liquid. Changes in temperature, 
due to alterations in the lamp voltage, result in 
changes in volume of the liquid. These changes 
in volume expand or contract the Bourdon tube 
so that it moves the stylus in the usual manner 
of a BT. 



Figure 22. Back of control panel. 


The card holder, in normal operation of the 
bathythermograph, moves upward in response 
to increasing pressure in the depth Bourdon 
tube, this increasing pressure being due to in¬ 
creasing depth of the submarine. In the SBCD 
the card holder responds in the same manner, 
but the pressure is applied by manual opera¬ 
tion of the sylphon bellows previously de¬ 
scribed. 

The instructor, at the start of a problem, 
moves the stylus to any desired temperature by 
turning the lamps full on with the rapid-change 
switch. This temperature is then maintained by 
adjustment of the temperature knob, with the 
rapid-change switch turned to normal. There¬ 
after, by adjusting the depth and temperature 
knobs, the instructor is able to trace on the 
card any thermal conditions desired, in simu¬ 
lation of actual sea conditions. 


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OPERATION 


211 


Is-W as Animated Trainer 



Figure 23. IS-WAS animated trainer. 


The is-was animated trainer [IS-WAS-AT], 
developed by CUDWR-NLL, is a lantern slide 
of the dials of an attack course finder [IS- 
WAS], with controls which enable the instruc¬ 
tor to vary the readings while the slide is in the 
projector. The images of the dials may be 
rotated with respect to each other and to the 
image of an outer fixed dial in a manner similar 
to the rotation of the dials of an IS-WAS. 


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GLOSSARY 


BT. Bathythermograph. 

BDI. Bearing deviation indicator. 

Chemical Recorder. An indicator which records range 
on chemically treated paper. 

DCPR. Depth charge pattern recorder. 

DRSB. Directional radio sono buoy. 

ERGT. Echo recognition group trainer. 

ERSB. Expendable radio sono buoy. 

FXR. Mechanical noisemaker towed from surface ships 
to decoy acoustic torpedoes. 

GCT. Navy General Classification Test. 

GET. Group listening teacher. 

GOT. Group operator trainer. 

HUSL. Harvard Underwater Sound Laboratory. 

IBM. International Business Machines. 

IES Coils. Inductive echo simulator coils, also known 
as projector simulator [PS] coils. 

JP, JT. Submarine sonic listening systems employing 
magnetostriction line hydrophones. 

MAD. Magnetic airborne detector. 

Magnetostriction Effect. Phenomenon exhibited by 
certain metals, particularly nickel and its alloys, 
which change in length when magnetized, or (Villari 
effect) when magnetized and then mechanically dis¬ 
torted, undergo a corresponding change in magnetiza¬ 
tion. 

MTB. Maintenance of true bearing. 

NLM. Noise level monitor. 

OAX Monitor. A portable sound gear monitor, with 
range from 15 to 26 kc. 

OTE. Operator training equipment. 

PBT. Primary bearing teacher. 

PS Coils. Projector simulator coils, also known as in¬ 
ductive echo simulator [IES] coils. 

QC. Standard Navy searchlight-type echo-ranging 
equipment using magnetostriction transducers. 


QFA. Sangamo series underwater sound attack teachers. 

QFD. Navy designation for advanced bearing teacher. 

QFE. Navy designation for primary bearing teacher. 

QFH. Navy designation for primary conning teacher. 

QFL. Navy designation for sound range recorder 

teacher, tactical range recorder teacher or phono¬ 
graph recorder teacher. 

QGB. Navy designation for a particular echo-ranging 
system utilizing a magnetostriction transducer and 
incorporating BDI features. 

QJB. Navy designation for a Rochelle salt echo-ranging 
system with BDI. 

RCG. Reverberation control of gain. 

Reverberation. Sound scattered diffusely back toward 
the source, principally from the surface or bottom, 
and from small scattering sources in the medium such 
as bubbles of air and suspended solid matter. 

SASAT. Shipboard antisubmarine attack teacher. 

SLC. Simultaneous lobe comparison. 

SRGT. Sound recognition group trainer. 

TDC. Torpedo data computer. 

Transducer. Any device for converting energy from one 
form to another (electrical, mechanical, or acoustic). 
In sonar, usually combines the functions of a hydro¬ 
phone and a projector. 

TVG. Time-varied gain. 

WCA. Navy designation for a submarine sonar system 
providing supersonic listening, echo-ranging, and 
sounding. 

WCSS. West Coast Sound School. 

WEB. Standard Navy small-sized magnetostriction echo¬ 
ranging gear. 

WFA. A submarine sonar system providing improved 
performance over the earlier WCA system. 

WHOI. Woods Hole Oceanographic Institution. 


RESTRICTED 


213 





BIBLIOGRAPHY 


Numbers such as Div. 6-311-M2 indicate that the document listed has been microfilmed and that its 
title appears in the microfilm index printed in a separate volume. For access to the index volume and to the 
microfilm, consult the Army or Navy agency listed on the reverse of the half-title page. 


Chapters 1-5 

1. Validity of Certain Tests for the Selection of Sound 

Operators, prepared by the Committee on Selection 
and Training of Sound Operators, Section C-4, 
NDRC, Mar. 6, 1942. Div. 6-311-M2 

2. A Survey of 4003 Audiograms in Relation to the 

Performance of Sonar Operators at the West Coast 
Sound School, Adelbert Ford, Report G-42, 
UCDWR, April 1944. Div. 6-311-M10 

3. The UCDWR Pitch-Memory Selection Test. A Re¬ 
port on Design Standards, Adelbert Ford, NDRC 
6.1-sr30-1413, Report U196, UCDWR, March, 1944. 

Div. 6-311-M8 

4. Revised Selection Procedure for Sonar Operators, 

A Report on Validating Research, Adelbert Ford, 
Stanley W. Osgood, and others, NDRC 6.1-sr30- 
1414, Report U197, UCDWR. Div. 6-311-M9 

5. Selection of Elementary Sound Materiel Students; 
Some Problems and Some Results, Robert L. 
French, CUDWR-NLL, Dec. 22, 1942. 

Div. 6-311-M6 

6. Bi-Weekly Report of Psychological Aspects of the 
Selection and Training of Sound Operators, Report 
ST-16, UCDWR, Aug. 23, 1943. Div. 6-310-MI 

7. The Selection of Sound Officers and Antisubmarine 

Warfare Officers, Report G42/TG192, CUDWR- 
NLL, Sept. 9, 1943. Div. 6-312-MI 

8. Selection Research on Sonar Officers, Technical 

Report on Validation Studies, Adelbert Ford, 
Stanley W. Osgood, and others, Report M235, 
NS-97, UCDWR, June 1944. Div. 6-312-M2 

9. The Relative Movement Test in Sonar Officer Se¬ 
lection, Report M-245, UCDWR, Aug. 5, 1944. 

Div. 6-312-M3 

10. The West Coast Sound School Training Program 

for the Tactical Sound Range Recorder Teacher, 
Navy QFL, William L. Jenkins, Report U190, 
UCDWR, March 1944. Div. 6-322.1-MI 

11. Selection and Training of Sound Operators, Wil¬ 
liam D. Neff, CUDWR-NLL, July 7, 1942. 

Div. 6-311-M3 

12. An Abbreviated Procedure for the Determination 

of Audiograms in the Selection of Sound Opera¬ 
tors, William D. Neff. Div. 6-311-MI 

13. The Use of Audiograms in the Selection of Sound 
Operators, William D. Neff, Dec. 14, 1942. 

Div. 6-311-M5 

14. Instructions for the Propeller Noise Discrimina¬ 

tion Meter, Robert T. Zern, Report P61/1293, 
CUDWR-NLL, Jan. 6, 1944. Div. 6-311-M7 

15. Tryout of the Propeller Noise Discrimination 


Meter at the West Coast Sound School, Stanley W. 
Osgood, Report P61/1378, CUDWR-NLL, Feb. 28, 
1945. Div. 6-311-M11 

16. Tryout of the Target Discrimination Test Records 

at the West Coast Sound School, Stanley W. Os¬ 
good, Report P61/1378, CUDWR-NLL, Feb. 28, 
1945. Div. 6-311-M12 

17. Proposed Classification and Training Program of 

ComSubTrain Pac, William D. Neff and Willard R. 
Thurlow, Report G42/PHR-T1, CUDWR-NLL, 
July 1944. Div. 6-310-M2 

18. ComSubLant Sonar, Radar Training Barge, 

George M. Gourly, Report P63/1414, CUDWR- 
NLL, Feb. 28, 1945. Div. 6-324-M3 

19. Basic Classification Program for the Training 
Command of the Submarine Force, Pacific Fleet, 
Administration of SubTrainPac Classification 
Tests and Questionnaires, Kinsley R. Smith and 
Willard R. Thurlow, Reports G42/PHR-40 and 
G42/PHR-48, CUDWR-NLL, Nov. 27, 1944. 

Div. 6-310-M3 

20. Administration of SubTrainPac Classification 
Tests and Questionnaires, Report G42/PHR-48, 
CUDWR, Nov. 30, 1944. 

21. Concluding Summary Report of the Selection and 
Training Committee, Dec. 14, 1944. 

22. Monthly Report; period from February 1 to Feb¬ 

ruary 28, 19^5, Part I, Studies, Equipment Devel¬ 
opment ayid Work of Laboratory Service Groups; 
Part II, Training Programs for Naval Personnel 
and Mechanical Aids to Training Programs, NDRC 
6.1-srll28-1942, Report G34A/1377, CUDWR- 
NLL, February 1945. Div. 6-310-M4 


Chapter 6 

PRIMARY BEARING TEACHER 

Primary Bearing Teacher, Henry E. Hartig, Firth 
Pierce, and George A. Bretell, Jr., OSRD 1063, 
NDRC C4-sr30-393, UCDWR, Nov. 5, 1942. 

Div. 6-321.1-M2 

Instructor's Manual for Use with the Primary Bearing 
Teacher, Report U59, UCDWR, May 1, 1943. 

Div. 6-321.1-M4 

For patent information, see Serial 555,144, Sept. 21, 
1944, Invention Report PC-4 sr-30, Patent 3. 

MIDGET BEARING DEMONSTRATOR 
Midget Bearing Demonstrator, Karl F. Sommermeyer, 


RESTRICTED 


215 


216 


BIBLIOGRAPHY 


OEMsr-30, Report M-256, NS-97, UCDWR, Sept. 14, 
1944. Div. 6-321.1-M6 

For patent information, see Serial 555,144, Oct. 21, 

1944, Invention Report PC-4 sr-30, Patent 3. 

ADVANCED BEARING TEACHER 

Service Manual for NDRC Bearing Teacher, RCA Man¬ 
ufacturing Co., Hollywood, Calif. [1942?]. 

Div. 6-321.1-MI 

Advanced Bearing Teacher, Henry E. Hartig, Firth 
Pierce, and George A. Bretell, Jr., NDRC 6.1-sr30- 
409, Report U18, Jan. 2, 1943. Div. 6-321.1-M3 

Instructor’s Manual for the Advanced Bearing Teacher, 
Report U69, June 8, 1943. Div. 6-321.1-M5 

For patent information, see Serial 483,620, Apr. 19, 
1943, Invention Report PC-4 sr-30, Patent 7. 

OTE-8 

Inductive Echo Simulator, O. Hugo Schuck, NDRC 

6.1- sr287-901, Report H-145, HUSL, June 28, 1943. 

Div. 6-321.5-MI 

Bearing Deviation Indicator Training Aid, Operator 
Training Equipment OTE Model 8, For Use with 
RCA Advanced Bearing Teacher, Type QFD, Neil E. 
Handel, B. A. Wooten, and Dwight E. Gray, OSRD 
4156, NDRC 6.1-sr287-1787, Report H-324, HUSL, 
Sept. 5, 1944. Div. 6-321.21-M3 

Operator Training Equipment, Model 8 Bearing Devia¬ 
tion Indicator Adapter for QFD, OSRD 5208, NDRC 

6.1- sr287-2063, HUSL, May 15, 1945. Div. 6-321.21-M5 

ECHO RECOGNITION GROUP TRAINER 

Echo Recognition Group Training as Developed for Use 
with the Echo Recognition Monitor Recorder, Model 
2 , Report U325, U. S. Navy Department and 
UCDWR, July 10, 1945.. Div. 6-321.4-MI 

For patent information, see Informal Report, Feb. 28, 

1945, Patent 67. 

OTE-2 AND OTE-10 

Inductive Echo Simulator, 0. Hugo Schuck, NDRC 

6.1- sr287-901, Report H-145, HUSL, June 28, 1943. 

Div. 6-321.5-MI 

Operating Training Equipment, Models 2 and 10, NDRC 

6.1- sr287-1555, Report H-282, HUSL, June 20, 1944. 

Div. 6-321.21-M2 

Operator Training Equipment, Models 2 and 10, NDRC 

6.1- sr287-2055, HUSL, Jan. 1, 1945. Div. 6-321.21-M4 
For patent information, see HUSL PC-sr-287, Patent 

35, OSRD 657, Navy Case 3918. 

BDI TRAINER 

Bearing Deviation Indicator Trainer, Clark E. Bradley, 
NDRC 6.1-sr30-1517, Report U218, UCDWR, May 
23, 1944. Div. 6-321.21-MI 

For patent information, see Invention Report PC-4 
sr-30, Patent 69. 


GROUP OPERATOR TRAINER 

Preliminary Instruction Manual for the Group Opera¬ 
tor Trainer, Report M376, NObs-2074 (formerly 
OEMsr-30), UCDWR, Feb. 8, 1946. Div. 6-321.3-MI 


Chapter 7 

1 . Preliminary Installation, Adjustment, Maintenance 

Instructions for Model QFL Tactical Range Re¬ 
corder Teacher, Report P21/533, CUDWR-NLL, 
May 8, 1944. Div. 6-322.1-M2 

2. Model QFL Tactical Range Recorder Teacher, 
William L. Jenkins, OSRD 5073, NDRC 6.1-srll28, 
1943, Report P21/1402, UCDWR, May 9, 1945. 

Div. 6-322.1-M4 

3. Recorder Trace Projector (RQ 10310 Recorder 

Projector Assembly) , Cecil E. Walton, NDRC 

6.1-srll28-1571, Report P39/711, CUDWR-NLL, 
Aug. 14, 1944. Div. 6-322.1-M3 


Chapter 8 

OPERATOR TRAINING EQUIPMENT, 
MODEL U (OTE-U) 

Installation, Operation, and Maintenance Instruction 
Book for Underwater Sound Attack Teacher, Model 
QFA and Model QFA-1, No. 94981, Sangamo Electric 
Co., Dec. 6, 1941. Div. 6-323.1-MI 

Inductive Echo Simulator, O. Hugo Schuck, NDRC 

6.1-sr287-901, Report H-145, HUSL, June 28, 1943. 

Div. 6-321.5-MI 

Bearing Deviation Indicator Training Aid for Use with 
Sangamo Attack Teacher, OSRD 3104, NDRC 6.1- 
sr287-1340, Report H-219, HUSL, Dec. 22, 1943. 

Div. 6-323.1-M2 

Bearing Deviation Indicator Training Aid for Use with 
Sangamo Attack Teacher QFA-3, NDRC 6.1-sr287- 
1440, Report H-246, HUSL, Feb. 21, 1944. 

Div. 6-323.1-M3 

Operator Training Equipment, Model U, OSRD 4932, 
NDRC 6.1-sr287-2059, HUSL, Mar. 1, 1945. 

Div. 6-323.1-M4 

Artificial Sonar Projector, OSRD 6080, NDRC 6.1- 
sr287-2054, HUSL, Sept. 1, 1945. Div. 6-321.5-M12 

ASSISTING SHIP PROJECTOR 

Preliminary Instruction Book for the Assisting Ship 
Projector, Model 1 , Serial No. 3334, Report M-373, 
NObs-2074, BuShips and UCDWR, Jan. 21, 1946. 

Div. 6-323-M4 

DEPTH CHARGE PATTERN RECORDER 

Preliminary Instruction Book for Depth Charge Pattern 
Recorder, Mark I, Model O, Installation, Operation 


RESTRICTED 




BIBLIOGRAPHY 


217 


and Maintenance, OSRD 3579, NDRC 6.1-sr30-1680, 
Report R173, UCDWR, May 1944. Div. 6-323-M2 
For patent information, see PC-4 sr-30, Patent 53. 


Chapter 9 

SHIPBOARD ANTI-SUBMARINE ATTACK 
TEACHER [ SASAT-B ] 

1. Shipboard Anti-Submarine Attack Teacher 
(SASAT B), Firth Pierce and Jay Schisel, OSRD 
3442, NDRC 6.1-sr30-1402, Report U186, III K 
337, UCDWR, Feb. 25, 1944. Div. 6-323.2-M7 
For patent information, see Serial 542,504, dated 
June 28, 1944, Invention Report PC-4 sr-30, 
Patent 31. 

PRACTICE ATTACK METER 

2. A Primary Standard Pressure Gradient Hydro¬ 
phone, NDRC C4-sr212-058, Mar. 2, 1942. 

3. “710 A Bone Conduction Receiver,” M. S. Hawley, 
Bell Laboratories Record, Vol. 18, September, 1939, 
pp. 12-14. 

4. London Mathematical Society Proceedings, H. 
Lamb, Dec. 14, 1882, pp. 50-56. 

5. Vibration Problems in Engineering, S. Timoshenko, 
Second Edition, pp. 405-410. 

6. Practice Attack Meter, OSRD 1367, NDRC, 6.1- 
sr346-830, BTL, Mar. 25, 1943. Div. 6-323-MI 

7. Some Characteristics of the Sound Field in the 
Sea, NDRC C4-sr30-083, UCDWR, Mar. 13, 1942, 
p. 34. 

ECHO INJECTOR 

8. Echo Injector, Karl Sommermeyer, Report U-302, 

UCDWR, Mar. 1, 1945. Div. 6-323-M3 

SHIPBOARD ANTI-SUBMARINE ATTACK 
TEACHER (SASAT A) 

9. A Device for Obtaining Bearing and Range Rate 
to Be Used as an Auxiliary to SASAT A, Carl 
Eckart, Report M-82, UCDWR, July 15, 1943. 

Div. 6-323.2-MI 

10. Shipboard Anti-Submarine Attack Teacher 

(SASAT A), Clark F. Bradley, OSRD 1933, 
NDRC 6.1-sr30-684, Report U-93, UCDWR, Aug. 
30, 1943. Div. 6-323.2-M3 

11. Preliminary Instruction Manual for the Ship¬ 
board Anti-Submarine Attack Teacher (SASAT 
A), Clark F. Bradley, and James M. Snodgrass, 
Report R-94, III K 289, UCDWR, Aug. 31, 1943. 

Div. 6-323.2-M4 

12. Installation, Operation and Maintenance Instruc¬ 
tion Book for Navy Model QFK Shipboard Sound 
Operator Trainer, NXss-30773, Stoddart Aircraft 
Radio Co., UCDWR, January 1944. Div. 6-323.2-M6 

13. Instructor’s Manual for Model QFK Shipboard 


Sound Operator Trainer, OEMsx’-SO, Report R-191, 
UCDWR, March 1944. Div. 6-323.2-M8 

14. Shipboard Anti-Submarine Sonar Trainer 

(SASAT A), Model V, Final Report, Edward G. 

Schmuckler, NDRC 6.1-sr30-1511, Report U211, 
UCDWR, May 5, 1944. Div. 6-323.2-M9 

15. For patent information, see Serial 535,472, dated 

May 13, 1944, Invention Report PC-4 sr-30, 

Patent 40. 

WEA-1 AND WEA-2 ADAPTERS FOR SASAT A 

16. WEA-1 and WEA-2 Adapters for SASAT, Clark 
F. Bradley, Report U-121, UCDWR, Oct. 22, 1943. 

Div. 6-323.2-M5 

SASAT SLIDE RULE 

17. SASAT Slide Rule, G. P. Harnwell and L. I. Schiff, 

OSRD 1932, NDRC 6.1-sr30-682, UCDWR, Aug. 
13, 1943. Div. 6-323.2-M2 

18. For patent information, see Serial 535,472, dated 

May 13, 1944, Invention Report PC-4 sr-30, 

Patent 40. 

19. Shipboard Submarine Periscope Attack Teacher, 
Gaylord P. Harnwell, UCDWR. Div. 6-325.1-M4 


Chapter 10 

1. Preliminary Instruction Book for Model BR-1 

Antisubmarine Practice Target Equipment with 
the Model Sl-AB Amplifier. Installation, Opera¬ 
tion and Maintenance Manual, Report U-70, NS- 
144, UCDWR, June 2, 1943, pp. 15-16. 

Div. 6-323.3-M7 

la. Ibid., pp. 5-6. 

2. Preliminary Instruction Book for Model BR-1 

Antisubmarine Practice Target Equipment with 
the Model S3-AB Amplifier. Installation, Opera¬ 
tion and Maintenance Manual, Report U-71, NS- 
144, UCDWR, June 11, 1943, pp. 15-16. 

Div. 6-323.3-M8 

2a. Ibid., pp. 5-6. 

3. Supplementary Notes on Preliminary Instruction 
Book for Model BR-1 Antisubmarine Practice 
Target with the Model S3-AB Amplifier, Report 
U-71a, UCDWR, Sept. 16, 1943, pp. 1-3. 

Div. 6-323.3-M9 

3a. Ibid., pp. 3-4. 

4. Preliminary Instruction Book for Model SR-2 
Antisubmarine Practice Target Equipment. In¬ 
stallation, Operation and Maintenance Manual, 
Report U-64, NS-144, UCDWR, May 14, 1943. 

Div. 6-323.3-M6 

5. Supplementary Instruction Book for Antisub¬ 

marine Practice Targets, OSRD 3806, NDRC 6.1- 
sr30-1684, Report R-200, NS-144, UCDWR, April 
1944. Div. 6-323.3-M11 

6. Echo Repeater Target, Surface Model RR-1, 


RESTRICTED 




218 


BIBLIOGRAPHY 


Edwin M. McMillan, David J. Evans, and William 
A. Myers, NDRC C4-sr30-399, Report U-l, 
UCDWR, Nov. 12, 1942. Div. 6-323.3-M2 

7. Operation, Maintenance and Installation Instruc¬ 
tions for Surface Model RR-1 Practice Target, 
Report U-15, NS-97, UCDWR, Dec. 14, 1942. 

Div. 6-323.3-M3 

8. Antisubmarine Practice Target, Keel Model KP-1, 

David J. Evans, T. Finley Burke, and Donald G. 
Reed, Report U-45, NS-144, UCDWR, Feb. 25, 
1943. Div. 6-323.3-M5 

9. Towed Submerged Antisubmarine Practice Target, 
Model SR-2, David J. Evans, T. Finley Burke, and 
Donald G. Reed, NDRC 6.1-sr30-736, Report U-42, 
NS-144, UCDWR, Feb. 25, 1943. Div. 6-323.3-M4 

10. Instruction Book for Model SR-5 Practice Target 
(Navy Model OAT Practice Target). Installation, 
Operation and Maintenance Manual, Report R-142, 
NS-144, UCDWR, January 1944. Div. 6-323.3-M10 

11. For patent information, see Serial 497,232, In¬ 
vention Reports PC-4 sr-30, Patent 10, and PC-4 
sr-30, Patent 51. 

12. Experimental Underwater Towed Model Echo Re¬ 

peater, Edwin M. McMillan, William A. Myers, 
and David J. Evans, NDRC C4-sr30-515, UCDWR, 
Sept. 1, 1942. Div. 6-323.3-MI 

13. Experimental Surface Model Echo Repeater, Wil¬ 
liam A. Myers and Edwin M. McMillan, UCDWR, 
June 20, 1942. 


Chapter 11 

ARTIFICIAL SONAR PROJECTOR 

1. Inductive Echo Simulator, O. Hugo Schuck, NDRC 

6.1-sr287-901, Report H-145, HUSL, June 28, 1943. 

Div. 6-321.5-MI 

2. Completion Report on Sound Gear Monitor, Sec¬ 
tion 6.1-sr287-2086, HUSL, Nov. 1, 1945. 

3. Neil Handel on Operational Testing Equipment, 
Neil E. Handel, HUSL, Oct. 5, 1943. 

Div. 6-321.6-MI 

4. Projector Simulator Coil Development Aims, 0. 
Hugo Schuck, HUSL, Feb. 2, 1944. Div. 6-321.5-M2 

5. Projector Simulator Coil Development Aims (con¬ 
tinued from Memorandum of Feb. 2, 1944), 0. 
Hugo Schuck, HUSL, Feb. 10, 1944. 

Div. 6-321.5-M3 

6. Spherical-Shaped Artificial Projectors, John O. 
Hancock, HUSL, Mar. 17, 1944. Div. 6-321.5-M4 

7. Operational Testing and Training Equipment 

Project Aims, O. Hugo Schuck, HUSL, Mar. 26, 
1944. Div. 6-321.5-M5 

8. Artificial Projector, John O. Hancock and O. Hugo 
Schuck, HUSL, May 23, 1944. Div. 6-321.5-M6 

9. Lag Line for Artificial Projector, John O. Han¬ 
cock, HUSL, July 26, 1944. Div. 6-321.5-M7 


10. Testing of Artificial Projector, O. Hugo Schuck 
and John O. Hancock, HUSL, Sept. 23, 1944. 

Div. 6-321.5-M8 

11. Distribution of OTE’s and Dynamic Demonstra¬ 
tors, F. V. Hunt, M91.20-238, HUSL, Oct. 21, 1944. 

12. Artificial Projector, O. Hugo Schuck, John O. Han¬ 

cock, and B. A. Wooten, NDRC 6.1-sr287-1786, 
HUSL, Nov. 1, 1944. Div. 6-321.5-M9 

13. Distraction Manual for Artificial Projector, 

HUSL, Dec. 1, 1944. Div. 6-321.5-M10 

14. Artificial QC Projector, Model 3, W. C. Kraft, 

HUSL, May 8, 1945. Div. 6-321.5-M11 

15. Artificial Sonar Projector, OSRD 6080, NDRC 

6.1- sr287-2054, HUSL, Sept. 1, 1945. 

Div. 6-321.5-M12 

BDI DYNAMIC DEMONSTRATOR 

16. Installation and Maintenance Manual for Bear¬ 

ing Deviation Indicator Unit, Model X-3, HUSL, 
Oct. 1, 1943. Div. 6-321.22-MI 

17. Bearing Deviation Indicator Dynamic Demonstra¬ 

tor, Charles R. Rutherford, B. A. Wooten, and 
Dwight E. Gray, NDRC 6.1-sr287-1557, HUSL, 
June 15, 1944. Div. 6-321.22-M2 

18. Bearing Deviation Indicator Dynamic Demonstra¬ 
tor, NDRC 6.1-sr287-2066, HUSL, June 30, 1945. 

Div. 6.321.22-M4 

OTE-9 (BDI Signal Generator) 

19. Inductive Echo Simulator, O. Hugo Schuck, NDRC 

6.1- sr287-901, Report H-145, HUSL, June 28, 1943. 

Div. 6-321.5-MI 

20. Operator Training Equipment, Model 9, Bearing 
Deviation Indicator Signal Generator, OSRD 5008, 
NDRC 6.1-sr287-2064, HUSL, Apr. 1, 1945. 

Div. 6-321.22-M3 

21. Instructor’s Manual for the JP-1 Training Pro¬ 

gram, Report P50/1197, N-118, CUDWR-NLL, 
Nov. 2, 1944. Div. 6-321.6-M2 


Chapter 12 

Recorder Water Noise for the Directional Radio Sonic 
Buoy Trainer, Glen D. Gillett, Report P52/945, 
CUDWR-NLL, May 29, 1944. Div. 6-326.3-MI 

Filter and Mixer Unit for the Directional Radio Sono 
Buoy Trainer, Robert T. Zern, Report P52/1037, 

CUDWR-NLL, July 21, 1944. Div. 6-326.3-M3 

Completion Report, Expendable Radio Sono Buoy, 
NDRC 6.1-srll28-1581, CUDWR-NLL, July 27, 1944. 
Report on Training Activities, Part I, Expendable 
Radio Sono Buoy; Part II, Directional Radio Sono 
Buoy, Report P52/1142, covering period from Apr. 
1, 1944 to Sept. 1, 1944, CUDWR-NLL, Sept. 25, 
1944. Div. 6-326.3-M4 

Directional Radio Sono Buoy Trainer, Joseph A. Bark- 


RESTRICTED 



BIBLIOGRAPHY 


219 


son, OSRD 5095, NDRC 6.1-srll28-1947, NS-106, 
CUDWR-NLL, May 1, 1945. Div. 6-326.3-M5 

Completion Report, The Directional Radio Sono Buoy, 
NDRC No. 6.1-srll28-2224, CUDWR-NLL, May 20, 
1945. 


Chapter 13 

PRIMARY CONNING TEACHER 

1. Primary Conning Teacher, A. W. Melloh, OSRD 

1845, NDRC 6.1-sr30-681, Report U-89, UCDWR, 
Aug. 14, 1943. Div. 6-322.2-M3 

A Conning Teacher, William E. Stephens, 
UCDWR, Aug. 29, 1942. Div. 6-322.2-MI 

Instruction Book for Primary Conning Teacher 
Model QEH, Sangamo Electric Co., June 1943. 
Instructor’s Manual for Model QFH Sound Train¬ 
ing Equipment (Conning Teacher), Edition B, 
Report R-192, UCDWR, March 1944. 

Div. 6-322.2-M4 

For patent information, see Serial 511,130, Nov. 20, 
1943, Invention Report PC-4 sr-30, Patent 44. 

ANIMATED TRAINERS 

2. Instructor’s Pamphlet for the Relative Bearing 

Animated Trainer, Report P47/936, CUDWR- 
NLL, July 1, 1944. Div. 6-326.2-M2 

3. Instructor’s Pamphlet for the Bearing Indicator 

Animated Trainer, Report P47/937, CUDWR- 
NLL, July 1, 1944. Div. 6-326.2-MI 

Training Equipment for Submarine Personnel, 
Report Gll/913, CUDWR-NLL, May 6, 1944. 

Div. 6-324-MI 

Animated Trainers B1AT, RBAT and IS-WAS- 
AT, Glen D. Gillett and Nelson W. Rodelius, 
NDRC 6.1-srll28-1598, Report P47/1193, NS-118, 
NLL, Oct. 31, 1944. Div. 6-326.2-M4 

OPERATIONAL BEARING RECORDER 

Operational Bearing Recorder, OSRD 3562, NDRC 
6.1-sr-287-1454, Report H-261, HUSL, Apr. 10, 
1944. Div. 6-326.1-MI 

Operational Bearing Recorder, NDRC 6.1-sr-287- 
2065, NS-97, HUSL, Mar. 1, 1945. 

Div. 6-326.1-M2 


Chapter 14 

NOISE LEVEL MONITOR TRAINER 

1. Instructor’s Handbook for the Noise Level Moni¬ 
tor Trainer, Report 4E/M2, CUDWR, 1945 [?]. 

Div. 6-324-M2 

SOUND RECOGNITION GROUP TRAINER 
Preliminary Instruction Book for the Sound Recog¬ 


nition Group Trainer, Report M-342, NObs-2074, 
UCDWR, July 20, 1945. Div. 6-324-M4 

RANGE INDICATOR TRAINER 

The Range Indicator Trainer, Report M-381, 
NObs-2074, UCDWR, Dec. 11, 1945. 

Div. 6-326-MI 

GROUP LISTENING TEACHER 

Preliminary Instruction Manual for the Group 
Listening Teacher, Model CXKG (WCA portion), 
Operation, Installation and Maintenance, Part I, 
Text; Part II, Illustrations, Report M-380, 
UCDWR, Mar. 15, 1946. Div. 6-324-M5 


Chapter 15 

PERISCOPE TRAINER 

1. Periscope Trainer Manual, N-118, Report P41/ 
1325, CUDWR-NLL, Feb. 5, 1945. 

Div. 6-325.1-M2 

General Specifications for the Periscope Trainer, 

NS-97, Report P41/841, CUDWR-NLL, July 11, 
1944. Div. 6-325.1-MI 

Periscope Trainer, Joseph A. Barkson, OSRD 
5233, NDRC 6.1-srll28-2213, N-118, Report P41/ 
1420, CUDWR-NLL, May 21, 1945. 

Div. 6-325.1-M3 

For patent information, see Invention Report 
PC6.1 srll28, Patent 76. 

CONNING OFFICER ATTACK 
TEACHER MODIFICATION 

2. Training Equipment for Submarine Personnel, 
Report Gll/913, CUDWR-NLL, May 6, 1944. 

Div. 6-324-MI 

3. Synchro Requirements for Attack Teachers, Glen 

D. Gillett, Report P40/P52/955, CUDWR-NLL, 
June 7, 1944. Div. 6-326.3-M2 

4. Conning Officer Attack Teacher, Glen D. Gillett, 

NS-257, Report P40/1147, CUDWR-NLL, Sept. 
23, 1944. Div. 6-322.2-M5 

5. Preliminary Installation, Operation, and Mainte¬ 
nance Insti~uctions for the Modified Mark 1 
Conning Officer Attack Teacher [COAT 1 ], Report 
P40/1156, CUDWR-NLL, Feb. 15, 1945. 

Div. 6-322.2-M6 

6. Modification of the Mark I Conning Officer At¬ 
tack Teacher, Glen D. Gillett, Harold Hultgren, 
and Nelson W. Rodelius, NDRC 6.1 srll28-1583, 
Report P40/1227, CUDWR-NLL, Feb. 19, 1945. 

Div. 6-322.2-M7 

TORPEDO ANGLE SOLVER DEMONSTRATOR 

7. Training Equipment for Submarine Personnel, 
Report Gll/913, CUDWR-NLL, May 6, 1944. 

Div. 6-324-MI 


RESTRICTED 



220 


BIBLIOGRAPHY 


SUBMARINE BAROMETER SIMULATOR 

8. Submarine Barometer Simulator, Report M-270, 

UCDWR, Oct. 28, 1944. Div. 6-325-MI 

For patent information, see Invention Report 
PC-4 sr-30, Patent 78. 

THE BATHYTHERMOGRAPH SIMULATOR 

9. The Bathythermograph Simulator, Report U360, 
NObs-2074, UCDWR, Sept. 13, 1945. 

Div. 6-325.2-MI 

SUBMARINE BATHYTHERMOGRAPH 
CLASSROOM DEMONSTRATOR 

10. Submarine Bathythermograph Classroom Demon¬ 
strator, Report M-363, NObs-2074, UCDWR, 

Sept. 20, 1945. Div. 6-325.2-M2 

IS-WAS ANIMATED TRAINER 

11. Training Equipment for Submarine Personnel, 
Report Gll/913, CUDWR-NLL, May 6, 1944. 

Div. 6-324-MI 

12. Instructor’s Pamphlet for the IS-WAS Animated 

Trainer, Report P47/1000, CUDWR-NLL, July 
10, 1944. Div. 6-326.2-M3 

13. Animated Trainers BIAT, RBAT, IS-WAS-AT, 

Glen D. Gillett and N. W. Rodelius, NDRC 6.1- 
srll28-1598, Report P47/1193, CUDWR-NLL, 
Oct. 31, 1944. Div. 6-326.2-M4 

14. Training Equipment for Submarine Personnel, 
Report Gll/913, CUDWR-NLL, May 6, 1944. 

Div. 6-324-MI 


GENERAL 

Test-Retest Reliability of Pitch Discrimination Tests, 
William D. Neff, CUDWR-NLL, Dec. 14, 1942. 

Div. 6-311-M4 

Installation, Operation and Maintenance Instructions 
for Model QFH Underwater Sound Equipment, Type 
CAN-55117 Conning Teacher, NXss-29059, Sangamo 
Electric Co., June 1943. Div. 6-322.2-M2 


Phonograph Recordings for Chapter 3 


In a number of cases preliminary editions of record¬ 
ings were issued. These are not listed separately but 
are mentioned under the headings for the final editions. 
Distributor and year of issue are given in parentheses. 

1. Demonstration Records: Echo Ranging Training 
Set (NavPers 11401 RA through 11404 RB, 1943). 

10 basic training records explaining echo ranging 
and doppler effect. 

2. Attack Procedure Records: Echo Ranging Training 
Set (NavPers 11460 RA through 11460 RB, 1943). 

8 records consisting of transcriptions of practice 
attacks made by a well-trained sonar team, using 
cut-on procedure (prior to BDI). 

3. Exercise Records: Echo Ranging Training Set 
(NavPers 11430 RA through 11435 RB, 1943). 


2 records for practice in search procedure and 5 
for practice in crossing target (dummy gear 
required). 5 records for practice in echo identi¬ 
fication. 

4. Listening Records: Sonar Training Set (NavPers 
11445 RA through 11448 RA, 1944). 

4 records of torpedo sounds and 3 records of 
FXR sounds, as heard over standard echo¬ 
ranging gear. 

5. Doppler Drill Records: Echo Ranging Training Set 
(NavPers 11415 RA through 11422 RA, 1944). 

Each series consists of a drill of 72 items and a 
test of 40 items. All items were made from sea- 
recorded reverberations and synthetic echoes. 
Series D-l: Elementary training; differences of 
0, 30, 60, 75 cycles. 

Series D-2: Intermediate training; differences of 
0, 14, 30, 45 cycles. 

Series D-3: Same as D-2 with background water 
noise added. 

Series D-4: Advanced training; background 
water noise and attenuated echoes. 

The D-Series of doppler drills and tests replaced 
the earlier series made by CUDWR and issued 
by BuAer (CS088894 through CS088899) in 
1943. The BuAer series used sounds from the 
advanced bearing teacher. 

6. Sonar Pitch-Memory Test (NavPers 11750 RA 
through 11751 RB, 1944). 

7. ASRB Recordings (CUDWR Series ASRB, Records 
1 through 17, 1943). 

A series of experimental recordings for training 
operators of the anchored radio sono buoy equip¬ 
ment. 11 records are demonstrations of under¬ 
water sounds; 6 are tests of sound recognition. 

8. Expendable Radio Sono-Buoy Training Records 
(BuAer Device 15P3, Records I through XX, 1944). 

14 demonstration records of sounds heard over 
ERSB. 2 target identification and turn count 
test records. 4 records for giving pencil-and- 
paper search problems. These records replaced 
the D-16 series of ERSB recordings made and 
distributed by CUDWR in 1942. 

9. Directional Radio Sono-Buoy Training Records 
(CUDWR DRSB Series, Records 1 through 10, 
1944). 

10 demonstration records for training operators 
in special features of DRSB. The ERSB train¬ 
ing records were also used in DRSB training. 

10. QFL Trainer Recordings (NavPers 11510-11518; 
11522-11530; 11534-11542; 11546-11554; 11558- 

11566,1944). 

Recordings of practice attacks on submarines, 
with 75-cycle tone added to key the recorders. 
Usable only with QFL trainer. Contents are 
tabulated below: 


Quantity 
of records 
12 

4 

2 

3 


Subject matter 

Basic explanations of recorder oper¬ 
ation and trace interpretation 
Demonstrations of changing target 
aspect 

Tests on target aspect change 
Demonstrations of knuckles and 
pillenwerfer 


RESTRICTED 




BIBLIOGRAPHY 


221 


3 Range rate and doppler drills 

10 Firing time drills, cut-ons, ahead 

thrown attacks 

6 Firing time drills, BDI, ahead 

thrown attacks 

3 Firing time drills, depth charge 

attacks 

2 Final test 

11. ERGT Trainer Recordings (UCDWR, 1945). 

Drill records for training in echo recognition. 
While designed for use with the ERGT, they may 
also be used by a trained instructor without the 
ERGT. Series ERT-3 replaced two earlier ex¬ 
perimental series. Contents of ERT-3: 

Subject matter 

Doppler training 
Contact classification 
Faint echo detection 
Cut-on drills 
Procedure drills 

Achievement tests on doppler, contact 
classification, faint echo detection 

Slides and Films 

1. Sighting Subs by Sound (SN-2637 a, b, c, 1943). 

Slide film in 3 parts for ERSB instruction. Ac¬ 
companied by disk recordings. 

2. Directional Radio Sono Buoy (CUDWR, 1944). 

Sound movie on operation and use of DRSB. 

Devices for Classroom Use 

1. Magnetic Ocean (UCDWR, 1944). 

8-in. ASW vessels and 6-in. submarine held 
magnetically to a 4x4 ft iron sheet. Elastic cord 
connecting ship and submarine permits con¬ 
tinuous demonstration of relative bearing and 
target angle. 11 units constructed for use at 
West Coast Sound School. 

2. Relative Bearing Animated Trainer (CUDWR, 
1944). 

Lantern slide representing a relative bearing 
scale. 

3. Bearing Indicator Animated Trainer (CUDWR, 
1944). 

Lantern slide representing the bearing repeater 
dials of a sonar stack. 


Phonograph Recordings for Chapter 5 

In a number of cases preliminary editions of record¬ 
ings were issued. These are not listed separately but are 
mentioned under the headings for the final editions. 
Distributor and year of issue are given in parentheses. 

1. JP Sonic Listening Records (NavPers 11720RA- 
11731RB, 1944). 

8 records of general instruction and demonstra¬ 
tion; 10 records on turn counting, including drills 
and tests; 6 drill and test records on recognition 
of target and nontarget sounds. Replaced the 
JP-1 Training Recordings, Series A, distributed 
by CUDWR, 1943. 


2. WCA Training Records (NavPers 11585RA- 
11592RB, 1944). 

4 records of general instruction and demonstra¬ 
tion; 4 records on turn counting, including 
drills and tests; 8 demonstration, drill, and test 
records on recognition of target and nontarget 
sounds. 

3. SRGT Recordings (UCDWR, 1945). 

Over 100 drill and test records covering such 
fields as target classification, target differentia¬ 
tion, echo-ranging detection, contact detection, 
turn counting and bow-stern identification; pre¬ 
pared for use with the sound recognition group 
trainer, but may be used independently if ad¬ 
ministered by a trained instructor. 

4. Target Discrimination Recordings (CUDWR, 
1945). 

9 drill and 3 test records presenting exercises as 
follows: sound of ship’s screws given as sample, 
then series of identical and very similar sounds 
from which student must pick out original 
sample. 

5. Submarine Telephone Talker Recordings (CUDWR, 
1944). 

Two records, the first containing examples of 
telephone talking as recorded over a submarine 
battle circuit during practice operations, the 
second pointing out typical errors made in the 
first and demonstrating correct procedures. 

6. QFM Trainer Recordings (CUDWR, 1944). 

3 records, distributed only with QFM trainer, 
containing examples of torpedo runs as recorded 
over TDM equipment, 60-c tones inserted at 
appropriate intervals to key the recorders. 

7. NLM Trainer Recordings (CUDWR, 1944). 

4 records of auxiliary sounds and background 
water noise to be played through the control 
unit of the trainer in order to produce ap¬ 
propriate readings on the NLM; records dis¬ 
tributed only with NLM trainer. 

Slides and Films 

1. The Fundamentals of Sound, Parts I and II (U. S. 
Navy Training Films SN 4090A and 4090B; dis¬ 
tributed by BuAer, 1944). 

Slide films with accompanying sound on records; 
Part I describes sound waves and their method 
of transmission, Part II covers refraction, re¬ 
flection, and doppler effect. 

2. Estimation of Angle-on-the-Bow, Parts I-V (U. S. 
Navy Training Films SN 4091 a, b, c, d, e, dis¬ 
tributed by BuAer, 1944). 

Silent slide films for training of submarine 
officers, replacing lantern slides originally used 
for this purpose. 

3. Instructional Slides for Submarine Training 
(numbers shown below distributed by BuAer, 
1944). 

Mainly reproductions of wall charts and dia¬ 
grams. Contents include: 

Quantity Identifying 

of slides numbers Subject matter 

49 LN 4069 a-aw General 

16 LN 4071 a-p Torpedoes 


RESTRICTED 



222 


BIBLIOGRAPHY 


34 

LN 

4073 

a-ai 

Engineering — 
Auxiliaries 

21 

LN 

4075 

a-u 

GM, V-16, 278A 
Diesel 

21 

LN 

4075 

v-ap 

GM, 8- 2 68 A 
Diesel 

25 

LN 

4077 

a-y 

Fairbanks 
Morse Engine 

16 

LN 

4079 

a-p 

Engineering 

miscellaneous 

36 

LN 

4081 

a-aj 

Electrical 

30 

LN 

4083 

a-ad 

Communications 


4. Lantern Slides for Sonar Training (CUDWR, 
1944). 

Used in basic classroom instruction, operation 
and maintenance. Separate set for each of the 
following equipments: 


Expendable Radio Sonic Buoy Equipment 
(CUDWR, April 1943) (D16/R188). 

4. Operator’s Manual for the Directional Radio Sono 
Buoy (CUDWR, December 1944) (D34/R1260). 

Sonar Maintenance 

1. Notes on Servicing Radio and Sound Equipment 
(BuShips, December 1942). 

Preliminary sonar maintenance manual developed 
from notes used at the West Coast Sound School. 

2. Sonar Material Handbook (COMINCH, February 
1943). 

The first general text and refei’ence covering the 
maintenance of underwater sound equipment. 

3. Sonar Bulletin (BuShips, first issue October 1943). 

Issued at intervals to present new material on 
maintenance. UCDWR aided in preparation of 
the first four issues. 


Equipment 

JP 

WCA 

JT 

NLM 

TDM 

DCDI 


Quantity 
of slides 
26 
14 
20 
5 
5 
4 


Classroom Devices 

1. Torpedo Angle Solver Demonstrator (CUDWR, 
1944). 

Large scale model of standard angle solver; one 
unit constructed for Submarine School. 

The following were animated lantern slides with 
movable dials for altering the image shown on the 
screen. Seven units of each were constructed for 
the Submarine School and other activities. 

2. Relative Bearing Animated Trainer (CUDWR, 
1944). 

3. IS-WAS Animated Trainer (CUDWR, 1944). 

4. Bearing Indicator Animated Trainer (CUDWR, 
1944). 


Instruction Books for Chapter 3 


Distributor and date of issue are shown in paren¬ 
theses. For laboratory developments only the most re¬ 
cent issues of instruction books are listed; in some 
instances these were preceded by temporary publica¬ 
tions which are now obsolete. 

Sonar Operation 


4. Sonar History Record (West Coast Sound School, 
March 1944). 

Contained blank forms which, when properly 
filled out, constituted a complete history of the 
installation and subsequent performance of the 
item of sonar equipment to which the book was 
assigned. Later replaced by the Sonar Equip¬ 
ment Log. 

5. Suggested Guide for Upkeep of Sonar Equipment 
(WCSS, March 1944). 

Step-by-step maintenance procedures for routine 
upkeep of echo-ranging equipment aboard ship. 
Prepared for local use, it was later printed in 
the 4th issue of the Sonar Bulletin. 

6. Sonar Maintenance Handbook (BuShips, August 
1944). 

An exhaustive loose-leaf book covering mainte¬ 
nance of all types of ASW sonar equipment. The 
first complete instruction book of its kind. 

7. Installation and Maintenance Manual for BDI 
Unit, Model X-3 (HUSL, October 1943). 

Later replaced by Maintenance Manual for BDI 
Equipments, prepared under Project NS-252. 

8. Preliminary Manual—Installation and Maintenance 
of the Expendable Radio Sonic Buoy Equipment 
(CUDWR, April 1943) (D16/R237). 

9. Preliminary Handbook of Maintenance Instructions 
for Radio Transmitting Equipment AN/CRT-4 
(XN-1) (CUDWR, November 1944) (D34/R1169). 

For Directional Radio Sono Buoy transmitting 
equipment. 

10. Installation and Maintenance Instructions of Re¬ 
ceiving Equipment AN/ARR-16 (CUDWR, Novem¬ 
ber 1944) (D34/R1167). 

For Directional Radio Sono Buoy receiving 
equipment. 


1. Operation of the Sound Range Recorder 
(COMINCH, March 1944). 

A general manual, prepared by CUDWR and 
ASDevLant, covering all phases of recorder oper¬ 
ation and trace interpretation. Preceded by a 
preliminary handbook on the interpretation of 
recorder traces, written and issued by CUDWR 
in 1943. 

2. Operator’s Manual for BDI Unit, Model X-3 
(HUSL, October 1943). 

3. Preliminary Manual—Operation and Use of the 


The following manuals were prepared under 
Project NS-252 (UCDWR in collaboration with 
BuShips). Some of them were issued after Division 
6 participation had ended. 

11. Sonar Equipment Log. 

12. Maintenance Manual for QCS/QCS-1 QCT/QCT- 
l/QCQ-l/QCR-l Sonar Equipment. 

13. Maintenance Manual for QCQ-2 Sonar Equipment. 

14. Maintenance Manual for BDI Sonar Equipment. 

15. Maintenance Manual for WCA Sonar Equipment. 


RESTRICTED 



BIBLIOGRAPHY 


223 


16. Maintenance Manual for QBE/QBE-1/QBE-3/QBE- 
3a Sonar Equipment. 

17. Maintenance Manual for WEA-2/WEA-2a Sonar 
Equipment. 

18. Maintenance Manual for Sonar Crystal Projectors. 

Radar and Radio 

The following manuals were prepared under 
Project NS-252. 

1. Radar Equipment Log. 

2. Radio Equipment Log. 

Bathythermograph 

1. Calculation of Sound Ray Paths Using the Re¬ 
fraction Slide Ride (NavShips 943, May 1943). 

2. Prediction of Souml Ranges from Bathyther¬ 
mograph Observations (NavShips 943-C2, March 
1944). 

The following manuals were part of the program 
of Project NS-308 (UCI)WR in collaboration with 
BuShips). Although most of them were issued after 
Division 6 participation had ended, the entire list 
is given here. 

3. The Sonar Range Book (NavShips 900,040, June 
1944). 

4. Manual for Bathythermograph Pilot Instructors 
(UCDWR, M-250, September 1944). 

5. Herald Ranges (NavShips 900,070, May 1945). 

6. Sound in the Sea (NavShips 900,112). 

7. Rules for Predicting Maximum Echo Ranges (Nav¬ 
Ships 900,111). 

Magnetic Airborne Detector 

1. Signal Recognition Manual AN/ASQ-1 and 
AN/ASQ-1A in Airplanes (Airborne Instruments 
Laboratory, April 1944). 6.1-srll29-1383. 

2. Handbook of Maintenance Instructions for CP- 
2ASQ-1 and CP-2/ASQ-1A Equipment (Airborne 
Instruments Laboratory, May 1944). 6.1-srll29- 
1386. 


Instruction Books for Chapter 5 

Only the most recent issues of instruction books are 
listed; in some instances these were preceded by 
temporary publications which are now obsolete. Dis¬ 
tributor and date of issue are shown in parentheses. 

Sonar Operation 

1. Submarine Sonar Operator's Manual (NavPers 

16167, November 1944). 

Standardized procedures for the operation of 
sonar equipment on submarines. 

2. Topside Listening (CUDWR, January 1944) 

(D24/R626). 

Operator’s Manual for JP sonic listening equip¬ 
ment. 

3. Operator's Manual for JT Sonar Equipment 

(CUDWR, May 1945) (D55/R1401). 

4. How to Operate the Cavitation Indicator and Noise 
Level Monitor (CUDWR, July 1945) (P55/TG156). 

5. Operator's Manual for the Torpedo Detection 


Modification of WCA-2 Equipment (CUDWR, 
March 1945) (P60/R1316). 

Sonar Maintenance 

1. Maintenance and Trouble-Shooting Instructions for 
Models JP-1, JP-2, and JP-3 Sound Receiving 
Equipment (CUDWR, May 1944) (D24/R837). 

A preliminary manual used in JP training pro¬ 
grams; later replaced by Maintenance Manual 
for JP-1/JP-2/JP-3 Sonar Equipment, prepared 
under Project NS-252. 

2. Preliminary Installation Instructions for Model JT 
Sonar Equipment (CUDWR, May 1945) 
(D55/R1314). 

3. Preliminary Manual: Installation, Operation, and 
Maintenance of the Depth Charge Direction In¬ 
dicator (CUDWR, December 1943) (D50/R614). 

4. Preliminary Installation and Maintenance Instruc¬ 
tions for the Depth Charge Range Estimator 
(CUDWR, February 1945) (D50/R1394). 

5. Preliminary Installation and Maintenance Instruc¬ 
tions for the Noise Level Monitor and Cavitation 
Indicator (CUDWR, February 1945) (P55/R1192). 

6. Preliminary Handbook of Installation, Operation, 
and Maintenance Instructions for the Torpedo De¬ 
tection Modification of the WCA-2 Sonar Equip¬ 
ment (CUDWR, February 1945). (P60/R1316). 

The following manuals were prepared as part of 
Project NS-252 (UCDWR in collaboration with 
BuShips) and some of them were issued after Di¬ 
vision 6 participation had ended. 

7. Maintenance Manual for WCA/WCA-1 Sonar 
Equipment. 

8. Maintenance Manual for WCA-2 Sonar Equipment. 

9. Maintenance Manual for JP-1/JP-2/JP-3 Sonar 
Equipment. 

Sonar Instructor’s Manuals 

1. Preliminary Instructor's Manual for the JP-1 
Training Program (CUDWR, November 1944) 
(P50/R1197). 

2. Training Program and Instructor's Manual for 
ComSubsLant Sonar-Radar Training Barge (YNg- 
22) (CUDWR, January 1945) (P63/R1308). 

3. Instructor’s Notes for First Week of Sonar Opera¬ 
tor’s Course Given by Pre-Commissioning Group, 
New London, Connecticut (CUDWR, February 
1945) (P63/R1415). 

4. Outlines of Lectures on the Noise Level Monitor 
and Cavitation Indicator (CUDWR, February 
1945) (P55/R1341). 

5. Outline of Training in the Use of Torpedo Detec¬ 
tion Modification of WCA-2 Equipment (CUDWR, 
February 1945) (P60/R1369). 

6. Outline of Instniction on the Depth Charge Direc¬ 
tion Indicator (CUDWR, February 1945) 
(D50/R1355). 

Voice Communications 

1. Submarine Telephone Talker’s Manual (NavPers 
16171, December 1944). 

Textbook for elementary instruction of submarine 
personnel in voice communication procedures. 

2. Standard Submarine Phraseology (CUDWR, 
January 1945). 


RESTRICTED 



224 


BIBLIOGRAPHY 


An official publication of standardized voice 
procedures and phraseology; distributed by Com- 
SubsLant. 

3. Ship’s Organization Chapter on Voice Communica¬ 
tions (CUDWR, January 1945). 

Distributed by ComSubsLant to be inserted in 
ship’s organization book of each submarine. 

4. Instructor’s Handbook for Basic Course in Sub- 
Marine Voice Communications (Harvard Psycho- 
Acoustic Laboratory, December 1944). 

Radar 

1. Fundamentals of Radar (CUDWR, February 1945) 
(P49A/R1389). 

2. Submarine Radar Operator’s Course (CUDWR, 
December 1944) (P63/R1267). 

Ba thythermogra pli 

1. Reference Textbook for Submarine Bathyther¬ 
mograph Field Engineers (WHOI, November 
1944). 


2. Lecture Notes on Use of Submarine Bathyther¬ 
mograph (WHOI, July 1945). 

This replaced earlier edition published by 

WHOI in January 1944. 

The following manuals were prepared by WHOI 
and UCDWR in collaboration with BuShips: 

3. Use of Submarine Bathythermograph Observations 
(NavShips 943-F, July 1943). 

4. Use of the Bathythermograph as an Aid in Diving 
Operations (NavShips 900,018, February 1944). 

The following manuals were prepared by Project 
NS-308 (UCDWR in collaboration with BuShips). 
All were completed after Division 6 participation 
had ended. 

5. Use of Submarine Bathythermograph Observations 
(NavShips 900,069). 

Issued in seven sections with a loose-leaf binder; 

constituted a complete revision of NavShips 

943-F of similar title. 

6. The Sea for Submarines (NavShips 900,018). 


RESTRICTED 



CONTRACT NUMBERS, CONTRACTORS, AND SUBJECT OF CONTRACTS 


Contract 

Number 

Name and Address 
of Contractor 

Subject 

OEMsr-20 

The Trustees of Columbia University 

New York, New York 

Studies and experimental investigations in 
connection with and for the development 
of equipment and methods pertaining to 
submarine wai'fare. 

OEMsr-1128 

The Trustees of Columbia University 

New York, New York 

Conduct studies and experimental investiga¬ 
tions in connection with and for the de¬ 
velopment of equipment and methods 
involved in submarine and subsurface 
warfare. 

OEMsr-1129 

The Trustees of Columbia University 

New York, New York 

Conduct studies and experimental investiga¬ 
tions in connection with the development 
and research work involving the applica¬ 
tion of magnetic methods to antisubmarine 
warfare including the development of air¬ 
borne equipment and methods for training 
personnel in the use of such magnetic 
methods, establishing the necessary labo¬ 
ratories and facilities for this purpose. 

OEMsr-30 

The Regents of the University of California 
Berkeley, California 

Maintain and operate certain laboratories 
and conduct studies and experimental in¬ 
vestigations in connection with submarine 
and subsurface warfare. 

OEMsr-31 

Woods Hole Oceanographic Institution 

Woods Hole, Massachusetts 

Studies and experimental investigations in 
connection with the structure of the super¬ 
ficial layer of the ocean and its effects on 
the transmission of sonic and supersonic 
vibrations. 

OEMsr-287 

President and Fellows of Harvard College 
Cambridge, Massachusetts 

Studies and experimental investigations in 
connection with (i) the development of 
equipment and devices relating to subsur¬ 
face warfare. 




RESTRICTED 


225 






SERVICE PROJECT NUMBERS 

The projects listed below were transmitted to the Executive 
Secretary, NDRC, from the War or Navy Department 
through either the War Department Liaison Officer for 
NDRC or the Office of Research and Inventions (formerly 
the Coordinator of Research and Development), Navy De¬ 
partment. 


Service 

Project Subject 

Number 


N-118 
Ext. NA-120 
NS-97 
Ext. NS-106 
Ext. NS-142 

Ext. NS-142 


NS-144 
NS-152 
Ext. NS-152 
NS-173 
NS-233 
NS-240 

Ext. NS-240 

NS-245 
Ext. NS-245 


NS-252 

NS-257 

NS-308 

NS-324 

NS-325 


NS-326 

NS-339 


Assistance in the submarine training program. 

Construction of a magnetic attack trainer. 

Selection and training program for sound operators. 

Buoy operator trainer for the ERSB. 

Request that a bearing deviation indication attachment 
be provided for attack teacher AirASDEVLANT. 

7 models of a dynamic demonstrator (for training in 
the operation of the BDI), consisting in part of an 
artificial projector and Navy type OAX monitor. 

Echo repeater target. 

Shipboard attack teacher. 

Training device, SASAT B Model II. 

Consulting services on SASAT Mark III equipments. 

Primary listening teacher. 

Consulting service on shipboard antisubmarine attack 
trainer. 

Consulting services to Librascope, Inc., on its develop¬ 
ment of a modification of the SASAT. 

Advanced listening teacher. 

Development and construction of group listening 
teacher. 

Preparation of supplements to sonar instruction books. 

Listening adjunct to submarine attack teacher. 

Sonar-surface and submarine bathythermograph in¬ 
struction program. 

Sonar group operator trainer (2 units of). 

BDI modification of the QFD advanced bearing teacher 
(Operational test equipment Model 8) 25 units of 
for service test from Underwater Sound Laboratory, 
Harvard, through a subcontractor. 

Artificial projector for operator training on shipboard 
monitor equipment Model OAX, 10 units of. 

Recognition recorder for use in training operators to 
recognize various ship and torpedo noises, four models 
of. 


NS-342 Attack teacher for QH type scanning sonar equipment. 
SC-64 Development and construction of expendable radio sonic 
buoy training device. 


226 


RESTRICTED 






INDEX 


The subject indexes of all STR volumes are combined in a master index printed in a separate volume. 
For access to the index volume consult the Army or Navy Agency listed on the reverse side of the half-title page. 


Achievement testing, sonar pei*- 
sonnel training, 2, 21-22 

ADP crystals for practice target 
transducers, 134 

Advanced bearing teacher, 20, 28, 
57, 71 

Age of personnel, sonar operator 
selection, 12 

Airborne Instruments Laboratory, 
4 

Aircraft Coordinating Group Bu- 
Ships, 3, 37 

Amplifier demonstrator, JP sonar 
training, 45, 160 

Amplifiers for antisubmarine prac¬ 
tice target equipment 
band-pass filter, 136-138 
comparison of specifications, 136 
frequency response, 136-138 
power supply, 136, 138 
Si amplifier, 136, 139 

51- AB amplifier, 136, 139 

52- AB amplifier, 136, 139 

53- AB amplifier, 136, 139 
S5-AB amplifier 136, 146 
U2-AB amplifier, 136, 138, 141- 

145 

Anchored sono radio buoy (ASRB) 
training, phonograph 
records, 28 

Angle-on-the-bow-estimation slide 
film, 56 

Antisubmarine attack trainers 
see Attack teachers 

Antisubmarine practice 

see Practice target equipment 

Antisubmarine warfare personnel 
selection and training 
see ASW 

Applied Psychology Panel, NDRC, 
5, 51 

Aptitude tests 

arithmetical reasoning test, 14- 
15 

Army Air Force tests, 16-17 
audiograms as measure of listen¬ 
ing ability, 41 

Bennett mechanical comprehen¬ 
sion test, 9-18 
clerical aptitude, 43 
enlisted personal inventory, 43 
for combat information center 
personnel, 18 

individual pitch discrimination, 

40 


inventory of musical background, 
11 

Iowa engineering and physical 
science aptitude test, 15 
mathematical comprehension and 
interpretation, 16 
mechanical aptitude (NavPers 
16524), 12, 43 
mechanical knowledge, 43 
mechanical relations (Air Force 
VI), 16-17 

Navy general classification test, 
10, 12, 14-15, 43 
near vision acuity tests, 12 
officer qualification, 16-18 
Otis test of mental ability, 9-10, 
40 

performance criteria, 13 
personal history questionnaires, 
9, 13, 43 

pitch-memory, 11-18 
reading (NavPers 16524), 14 
reading and arithmetical reason¬ 
ing, 12, 43 

relative movement, 17-18 
Seashore measures of musical 
talent, 9-12, 16-17, 40 
sonar pitch-memory, 11-18 
surface development (Air Force 
HI), 17 

Army Air Force aptitude tests, 
16-17 

Artificial reverberation 

see Reverberation simulation 

Artificial sonar projector, 60, 148- 
155 

frequency response, 151-153 
phase shifter, 151 
principle of operation, 149 
production of in-phase and 
quadrature voltages, 151 
projector unit, 152-153 
simulation of transmitting di¬ 
rectivity pattern, 152-153 
theory,149-150 

typical split projector patterns, 
155 

typical unsplit projector pat¬ 
terns, 153-155 

Askania diving trainer, bathy¬ 
thermograph simulator 
(TBS), 55,. 203-209 

ASRB (anchored sono radio buoy) 
recordings, 28 


Assisting ship projector (ASP), 
96-98 

azimuth control, 97, 98 
projector, 96 
rudder control, 98 
speed control, 98 
ASW Instructors School, 3, 16 
ASW Operation Research Group, 
34 

ASW sonar maintenance personnel, 
selection, 1, 13-16 
Key West Sound School plans, 
15 

San Diego Sound School plans, 
13-15, 37 

ASW sonar officers 
selection, 1, 16-17 
training, 19, 36-37 
ASW sonar operator selection, 1, 
9-13 

age of personnel, 12 
aptitude tests, 9-11 
audiometer tests, 11 
defective hearing, 11 
final 2-screen test, 12 
fleet selection, 11 
initial 2-screen method, 9-10 
previous education, 12 
recommendations, 13 
reliability of tests, 10 
shipboard selection tests, 11 
tonal tests, 11 

ASW sonar operator training, 1-4, 
7 

achievement testing, 21-22 
synthetic trainers, 57-81 
training programs for laboratory 
developments, 35-39 
Attack course finder, animated 
trainer, 211 

Attack procedures, training 

demonstration by magnetic ocean, 
28 

drills on synthetic trainers, 22 
evaluation with practice attack 
meters, 125-132 

phonograph recordings for per¬ 
sonnel training, 24-28 
practice runs at sea, 21 
Attack teachers 

see also Sangamo attack teacher; 

SASAT A; SASAT B 
azimuth grid, 99 

checking systems for perform¬ 
ance grading, 22 


RESTRICTED 


227 


228 


INDEX 


conning officer attack teacher, 
193-197 

Mark I attack teacher, 56, 193 
OTE-2—OTE-IO attack simula¬ 
tors, 36, 57, 60-68 
primary conning teacher, 33 
scoring methods, standardized 
attack runs, 21, 22 
Audiometer studies 

as measure of listening ability, 
41 

classification of audiograms, 41 
for sonar operator selection, 11, 
41-42 

four-frequency audiogram for 
hearing classification, 41 
recommendations, 13 
seven-frequency audiogram for 
hearing classification, 41 
Auditory tests 

see Listening ability tests 
Automatic problem generator 
in advanced bearing teacher, 28 
in group listening teacher, 186- 
188 

in group operator trainer, 29 
in SASAT, 33 

Balopticon, Bauseh and Lomb, 87 
Barber-Coleman recorder, 172 
Barge monitoring equipment, 192 
Barometer simulator, submarine, 

202- 204 

circuit operation, 203-204 
description, 202-203 
Barrel-type stationary repeater 
targets, 32 

Bathythermograph simulator 
(TBS), 55, 203-209 
amplifier and thyratron unit, 
208-209 

bathythermograph mock-up, 209 
control unit, 204-205 
depth selsyn unit, 209 
elevator unit, 206 
lamp assembly, 207-208 
motor unit, 209 
operation, 204 
track assembly, 205-206 
translator unit, 206-207 
Bathythermograph training pro¬ 
gram, 3, 5, 37, 54-55 
bathythermograph simulator, 55, 

203- 209 

classroom demonstrator, 209-210 
field instruction, 54 
instruction books, 37, 54-55 
Bauseh and Lomb Balopticon, 87 
BD-1 transducer, 134-136, 139-140 


BDI adjustment signal generator, 
157-160 

circuits, 158-160 
description, 157-158 
l'equirements, 158 

BDI dynamic demonstrator, 36, 
156-157 

BDI trainer, 57, 68-72 

advanced bearing teacher con¬ 
nection, 71 

attack teacher connection, 71 
bearing control 68-69 
CRO amplifiers, 69-71 
description, 68 

recommended improvements, 71- 
72 

reverberation amplification and 
rectification, 69 
right-left echo channels, 68 

BDI training, 3, 20, 36-37 
BDI trainer, 57, 68-72 
conning officer instruction, 36, 37 
dynamic demonstrator, 36, 156- 

157 

maintenance instruction, 36, 156- 

158 

operator instruction, 36 
OTE-4; 89-95 

OTE-8 training unit, 36, 57, 68 
OTE-9 adjustment signal gen¬ 
erator, 157-160 
trace interpretation, 36 
with Primary Conning Teacher, 
167-169 

Bearing deviation indicator 
see BDI 

Bearing recorders 
British AS407; 174 
operational bearing recorder, 
171-174 

Bearing trainers 

advanced bearing teachers, 28, 
36, 57 

animated trainer, 171 
BDI trainer, 68-72 
checking systems for perform¬ 
ance grading, 22 
development for sonar training, 
19-20 

midget bearing demonstrator, 29, 
57 

primary bearing teacher, 29, 57 

Bennett mechanical comprehension 
test 

correlation with relative move¬ 
ment test, 18 

use in sonar operator selection, 
9-17 

Blimp operation simulated by MAD 
trainer, 39 


BR-1 buoy model A/S practice 
target, 139 

British bearing recorder AS407, 
174 

Buoy for marking submarine posi¬ 
tion, 133 

Buoy-type BR-1 practice target, 139 

CD-I transducer, 134-136, 141 
CG-1 transducer, 136, 139, 141 
Chemical sound range recorder, 
operator training 
see Range recorder operator 
training 

CIC (combat information center) 
training 
aptitude test, 18 
primary conning teacher, 33 
Circular projector, vector analysis 
of output, 150 

CJ-1 transducer, 136, 139, 141 
Classification program for Com- 
SubPac, 43-44 
Clerical aptitude test, 43 
Coleman-Barber recorder, 172 
ComAirLant Sono Buoy School, 3, 
37-38 

Combat information center (CIC) 
training 
aptitude test, 18 
primary conning teacher, 33 
Commanding officers’ sonar courses, 
47 

Communications officers’ sonar 
courses, 47 

ComSubsLant sonar-radar training 
barge, 46, 47 

ComSubPac classification program, 
43-44 

ComSubs7thFleet sonar training 
program, 46 

ComSubTrainPac sonar training 
program, 43, 46 

Conning officer attack teacher 
modification, 193-197 
auxiliary control cabinet, 196 
installation, 193-194 
instructor’s repeater, 196 
periscope support table, 196 
power drive for conning tower, 
196 

sky canopy and lighting effects, 

196 

sound injectory, 196-197 
submarine course and speed re¬ 
peater, 195-196 
target bearing cam, 194-195 
Conning officer training 

attack teacher modification, 193- 

197 


RESTRICTED 



INDEX 


229 


primary conning teacher, 167-169 
use of SASAT, 33 
Conning teacher 

see Primary conning teacher 
Crystal sensitivity, variation with 
temperature, 136 

Curriculum planning, Navy sound 
schools, 2, 5, 20 

Dl, D2, D3 classification, audio- 
grams, 41 

DCDI (depth charge direction in¬ 
dicator) training, 50 
DCRE (depth charge range esti¬ 
mator), 50 

Depth charge driller, 99-101 
Depth charge pattern recorder, 32, 
99-101 

electric punches, 99-100 
series relay, 100-101 
solenoid circuits, 100 
thermal cutout switch, 100-101 
Depth-temperature patterns, bathy¬ 
thermograph simulator, 203- 
204 

Directional radio sono buoy, train¬ 
ing program, 20, 37-38 
Directional radio sono buoy 
trainer, 162-166 
amplifier and talk-back, 166 
description, 162-164 
playback, 166 

signal simulator system, 164-165 
synchro systems, 165-166 
Directivity patterns, practice tar¬ 
get transducers, 134-135 
Doppler discrimination tests, 13, 
17, 22 

Doppler drill, 22, 24 
DRSB trainer 

see Directional radio sono buoy 
trainer 

Echo injector, 33, 102-104 

Echo oscillator, SASAT A, 105-107 

Echo ranging training 

phonograph records, 24-28 
practice target equipment, 133- 
147 

Echo recognition group trainer 
(ERGT), 20, 34, 57-59 
echo recognition monitor re¬ 
corder, 58-59 
electrical circuits, 59 
phonograph recordings, 28, 32, 

58 

sound discrimination drill exer¬ 
cises, 32 

station keys, 58-59 

tank and paper driver assembly, 

59 


use in instructor training, 22 
use in operator training, 22 
Echo repeaters as practice targets 
see Practice target equipment 
Echo simulation 

in artificial sonar projector, 148- 
155 

in conning officer attack teacher 
modification, 197 
in group operator trainer, 74 
in OTE-2; 63-65 
in OTE-4; 92-94 

in practice target equipment, 
133-134 

in SASAT B, 112-114, 117-121 
Echo simulator coils 

in artificial sonar projector, 148- 
149 

in OTE-2; 60-61, 66 
in OTE-4; 91-92 

Elementary range recorder teacher, 
31, 82-83 

Enlisted personal inventory, 43 
ERGT 

see Echo recognition group 
trainer (ERGT) 

Expendable radio sono buoy 
(ERSB) training, 3, 37-38 
ERSB trainer, 162, 166 
phonograph records, 38-39 

Facsimile system, sound recogni¬ 
tion group trainer, 178-179 
Film strip, used in periscope 
trainer, 197-199 

Firing time analyzer, sound range 
recorder 

as performance criterion, sonar 
operator training, 22 
simulated in recorder trace pro¬ 
jector, 31 

Fleet Sound School, Key West, 1 
curriculum revision, 20 
instructors, 34 

selection of sonar maintenance 
men, 15 

Frequency response, practice target 
amplifiers, 136-138 
“Fundamentals of Sound” slide 
film, 50 
FXR noise 

phonograph records, 24-28 
simulated in group operator 
trainer, 74 

General classification test (GCT), 
10, 12, 14-15, 43 

Group listening teacher, 47-49, 186- 
192 

bearing information, 189-191 


generation of own-screw sounds, 
189 

generation of target-screw 
sounds, 189 

random noise generator, 189 
simulation of echo-ranging sig¬ 
nals, 191-192 

simulation of torpedo noise, 192 
Group operator trainer (GOT), 20, 
29, 72-81 
advantages, 72 
BDI simulation, 36 
checking systems for perform¬ 
ance grading, 22 
coupling stack training mechan¬ 
isms, 81 

description, 72-73 
follower chassis, 76 
grading recorder, 81 
indicators, 80-81 
keying chassis, 74, 76 
master station console, 73 
program generator, 74, 76-79 
propeller modulation, 74 
simulated transducer, 74, 79-80 
sound effect simulation, 74-76 
student station, 73 
Group trainers, 57 

advanced bearing teacher, 20, 28, 
57 

assisting ship projector, 96 
barge monitoring equipment, 192 
‘BDI trainer, 68-72 
DRSB trainer, 162-166 
echo recognition group trainer, 
20, 31, 34, 57-59 
ERSB trainer, 162 
group listening teacher, 47-49, 
186-192 

group operator trainer, 20, 29, 
72-81 

OTE-4; 89-95 
OTE-10; 66 

QFL tactical range recorder 
teacher, 83-86 

range indicator trainer, 180-183 
recorder trace projector, 31, 86- 
88 

sound recognition group trainer, 
175-179 

HI, H2, H3 and H4 audiogram 
classification, 41 

Head depressor for towed practice 
target equipment, 145-147 
Hearing classifications, 41 
Hearing defects 

influence on listening perform¬ 
ance, 42 


RESTRICTED 



230 


INDEX 


significance in sonar operator 
selection, 11 
Hearing tests 

see Listening ability tests 
Hydrophones 

see also Transducers 
in practice attack meter, 126- 
127 

vector analysis of output, 149-150 

Instruction manuals, 24, 35 

bathythermograph training, 37, 
54-55 

DCDI and DCRE equipment, 50 
JP sonar, 45 
JT sonar, 49, 50 
noise level monitor, 50 
periscope trainer manual, 202 
radio sono buoy training pro¬ 
grams, 37-39 
SASAT A, 104 

sound range recorder training, 
24 

submarine sonar and radar, 50 
TDM equipment, 50 
Instructors, Navy Sound Schools, 
2, 5, 34 

criticism of recorded lectures, 22 
instructor training, 22 
Interphone (submarine voice com¬ 
munication training device), 
53-54 

Inventory of musical background 
(aptitude test), 11 
Inverse time-varied gain, 60-61, 64- 
65 

Iowa engineering and physical sci¬ 
ence aptitude test, 15 
IS-WAS animated trainer, 211 

JP amplifier for noise level moni¬ 
tor trainer, 184, 185 
JP sonar training, 45-50, 161 

amplifier demonstrator for main¬ 
tenance training, 45, 160 
group listening teacher, 47-49, 
186-192 

phonograph recordings, 45 
sonar-radar training barge, 47 
training courses, 45 
training kits, 45-46 
training manuals, 45 
trouble injectors for mainte¬ 
nance training, 161 
JT sonar training, 49-50 

Key West Sound School, 1 
curriculum revision, 20 
instructors, 34 

selection of sonar maintenance 
personnel, 13-16 


K-gun arrangement simulation by 
depth charge pattern re¬ 
corder, 100 

Kollmorgen Corporation type II 
periscope, 197 

KR-1 A/S practice target, 140-141 

Laboratory development training 
programs 

see Training programs for sonar 
laboratory developments 

Lantern slides for sonar training, 
28, 56 

bearing indicator animated 
trainer, 171 

DCDI and DCRE training, 50 
ERSB training program, 37 
IS-WAS animated trainer, 56, 
211 

JT sonar, 49, 50 
relative bearing animated 
trainer, 171 

Line hydrophone, vector analysis 
of output, 149-150 

Listening ability tests 

individual pitch discrimination, 
40 

inventory of musical background, 
11 

recommendations, 13 
Seashore measures of musical 
talent, 9, 11-12, 16, 40 
sonar pitch memory test, 11-18 
value of audiograms as criterion, 
41, 42 

Listening teachers 

advanced listening teacher, 49 
group listening teacher, 47-49, 
186-192 

primary listening teacher, 47, 49 
problem generator, 49 

MAD (magnetic airborne detector) 
training program, 4, 20, 38- 
39 

magnetic attack trainer, 39 
pantograph tactics trainer, 39 

Magnetic attack trainer, 39 

Magnetic ocean demonstrator, 28, 
170 

Magnetostriction effect, definition, 
213 

Maintenance manuals 

DCDI and DCRE equipment, 50 
JP sonar, 45 
JT sonar, 49, 50 
noise level monitor, 50 
periscope trainer, 202 
TDM equipment, 50 


Maintenance personnel, selection, 1 
Key West Sound School pro¬ 
gram, 15 

San Diego Sound School pro¬ 
gram, 13-15 

Maintenance personnel, training 
instruction books, 24 
submarine school program, 49 
Maintenance training devices, 148- 
161 

artificial sonar projector, 148-155 
EDI adjustment signal gener¬ 
ator, 157-160 

BDI dynamic demonstrator, 156- 
157 

JP amplifier demonstrator, 160 
trouble injectors, 161 
Mark I attack teacher 

conning officer attack teacher 
modification, 193 
sound injector, 56 
Mark III periscope trainer, 197-202 
Mark VIII torpedo angle solver 
demonstrator, 56, 202 
Marker buoy for submarine posi¬ 
tion, 133 

Mathematical comprehension and 
interpretation test, 16-17 
Mechanical aptitude test (Nav- 
Pers 16524), 12, 43 
Mechanical comprehension test 
(Bennett), 9, 12, 14, 18 
Mechanical knowledge test, 43 
Mechanical relations test (Air 
Force VI), 16-17 

Medical Research Department, 
Submarine Base, New Lon¬ 
don, 4, 40 

Midget bearing demonstrator, 29, 
57 

Model chemical recorder, 31 
Monitor recorder, SRGT, 179 
Motion pictures 

for radio sono buoy training, 38- 
39 

for sonar operator training, 28 
Motor coordination tests, recom¬ 
mendation, 13 

“Mousetrap” training program, 35 
Musical background test, 11 

N, ND1 and ND2 hearing classifi¬ 
cation, 41 

Navy general classification test, 10, 
12, 14-15, 43 
Navy Sound Schools 
achievement testing, 2 
curriculum planning, 2, 20 
instructor training, 2, 34 


RESTRICTED 



INDEX 


231 


sonar maintenance man selection, 
13-15 

submarine sonar training pro¬ 
grams, 47-49 
training aids, 2 

NLM sonar equipment, training, 50 
Noise level monitor trainer, 183- 
185 

control unit, 184-185 
phonograph recordings, 50, 185 
Noisemakers 

phonograph recordings, 24 
simulation in group operator 
trainer, 74 

Oceanography instruction 

bathythermograph simulator, 55, 
203-209 

classroom demonstrator, 209-210 
field instruction, 54 
instruction manuals, 37, 54 
Officer qualification test, 16-18 
Officers, sonar 

ASW officer training, 19, 36 
selection methods, 1, 16-17 
submarine officer training, 47-49 
Operational bearing recorder, 171- 
174 

disadvantages, 174 
modification of Barber-Coleman 
recorder, 172 

recommendations for future de¬ 
sign modification, 173-174 
Operator selection, sonar 

see ASW sonar operator selec¬ 
tion; Submarine sonar oper¬ 
ator selection 
Operator training, sonar 

see ASW sonar operator train¬ 
ing; Submarine sonar oper¬ 
ator training 

Operator training equipment, sonar 
see OTE; Trainers 
Operator’s manuals 

see Instruction manuals 
Oscillator for SASAT A, 105-107 
OTE-2 attack simulator, 36, 57, 60- 
66 

echo simulation, 65 
electronic unit, 61, 63-65 
keying control, 66 
mechanical unit, 61-63, 66 
operation with BDI, 61 
paper drive, 63 
program cams, 63 
projector simulator coils, 66 
reverberation simulation, 60-61, 
63-65 

target bearing, doppler, and 
range cams, 66 


OTE-4; 36, 89-95 

BDI simulation, 91-92 
description, 89-91 
echo generation, 92-94 
projector simulator coil arrange¬ 
ment, 91-92 

propeller-noise generation, 95 
reverberation generation, 92-94 
synchronization circuits, 94-95 

OTE-8 synthetic BDI trainer, 36, 
57, 68 

OTE-9 BDI adjustment signal gen¬ 
erator, 157-160 
circuits, 158-160 
description, 157, 158 
requirements, 158 
use in BDI maintenance train¬ 
ing, 36 

OTE-10 group attack simulator, 57, 
66 

description, 66-67 

ship’s course simulation, 67 

simulator coil placement, 67 

Otis test of mental ability, 9-10, 40 

Pantograph tactics trainer, 39 

Performance criteria, aptitude 

tests, 13 

Periscope trainer, 56, 197-202 
horizontal training, 200 
illumination, 198 
instruction and maintenance 

manual, 202 
optical system, 198 
ship finder and recognition 
charts, 200-202 
stadimeter, 200 
target film strips, 197-199 
vertical sweep and simulated 
ship roll, 199-200 

Personal history questionnaires, 9, 
13, 43 

Personnel selection, sonar 
see also Aptitude tests 
ASW maintenance personnel, 1, 
13-16 

ASW officers, 1, 9-13, 16-18 
ASW operators, 1, 16-17 
research, 6 

submarine operators, 4-5, 40-44 

Personnel training, sonar 

see also Instruction manuals; 
Trainers 

achievement testing, 2, 21-22 
ASW maintenance personnel, 
148-161 

ASW officers, 19, 36 
ASW operators, 1-4, 7, 21-22, 
35-39 


submarine maintenance person¬ 
nel, 49 

submarine officer, 47-49 
submarine operators, 4-8, 45-51 
P.E.T.N., Hercules Powder Com¬ 
pany explosive, 126 
Phonograph recordings, 2, 24-28 
ASRB training, 28 
DRSB training, 37, 38 
ERGT drill and test records, 28, 
32, 58 

ERSB training, 37-38 
FXR noise, 24 
instructor training, 22 
JP sonar training, 45 
noise level monitor trainer, 50, 
185 

QFL tactical range recorder 
teacher, 30-31, 83, 86 
QFM torpedo detection modifica¬ 
tion trainer, 186 
sonar-radar training barge, 47 
SRGT, 49, 179 

submarine telephone talker train¬ 
ing, 53 

target discrimination test re¬ 
cordings, 42 

WCA supersonic listening, 50 
Phraseology standardization, sub¬ 
marine commands and re¬ 
ports, 52 

Pitch discrimination 

pitch-memory test, 11-18 
Seashore measures of musical 
talent, 9, 11-12, 16-17, 40 
Point projectors, output analysis, 
149-150 

Practice attack meter, 125-132 
amplifying and recording sys¬ 
tem, 125, 127-130 
calculating chart, 125, 130-131 
calibration, 130-131 
hydrophone, 126-127 
loading and release mechanism, 
125-126 

principles of operation, 125, 127- 
130 

projectile, 125-126 
range sensitivity, 125 
recommendation, 132 
subcaliber depth charges, 125 
Practice target equipment, 32-33, 
133-147 

advantages and disadvantages, 

133 

amplifiers, 136-138 
barrel-type stationary repeater, 
32 

Model KR-1; 140-141 
Model RR-1; 139-141 


RESTRICTED 



232 


INDEX 


Model SR-2; 141-146 
Model SR-5; 146-147 
principles of operation, 133 
submersible repeater target, 32 
transducer characteristics, 133- 
136 

Primary bearing teacher, 29, 57 
Primary conning teacher, 33, 167- 
169 

barrage release circuit, 169 
BDI simulation, 167-169 
description, 167 

destroyer steering motor circuit, 
169 

optical unit, 169 

principles of operation, 167-169 
submarine steering motor cir¬ 
cuit, 169 

Problem generators 

assisting ship projector, 96-98 
gi’oup listening teacher, 49 
Program generator for group 
operator trainer, 76-79 
Projector simulator (PS) coils 
in artificial sonar projector, 148- 
149 

in OTE-2; 60-61, 66 
in OTE-4; 91-92 
Projectors 

see Transducers 
Pronunciation of numerals, 53 
Propeller modulation simulated in 
group operator trainer, 74 
Propeller noise discrimination 
meter, 42 

Propeller noise generation, OTE-4; 
95 

Psycho-Acoustic Laboratory, Har¬ 
vard University, 5, 52 

QC echo-ranging equipment 

interference with practice at¬ 
tack meter, 126 

SASAT A echo injector, 102-104 
QFA-2 

see Sangamo attack teacher 
QFD advanced bearing teacher, 20, 
28, 71 

QFE primary bearing teacher, 28 
QFH 

see Primary conning teacher 
QFK 

see SASAT 

QFL tactical range recorder 
teacher, 20, 30, 83-86 
adapted for torpedo detection 
modification trainer, 186 
amplifier control unit, 83-85 
average firing time as perform¬ 
ance criterion, 22 


description, 83-86 
experimental instruction pro¬ 
grams, 34 

instruction manuals, 24 
phonograph recordings, 30-31, 
83, 86 

scores used in sonar officer 
selection, 17 

sound range recorders, 85-86 

QFM torpedo detection modifica¬ 
tion trainer, 50, 186 

Radar training program, sub¬ 
marine school, 51 

Radio sono buoy training pro¬ 
grams, 37-39, 162-166 
DRSB trainer, 37-38, 162-166 
ERSB trainer, 37-38, 162, 166 
field service, 37 

instruction books and training 
recordings, 37-39 
motion picture, 38, 39 
phonograph records, 38-39 
slide films, 37-39 
sono buoy school, 38 

Raft-suspended RR-1 practice tar¬ 
get, 139-141 

Range indicator trainer, 180-183 
analysis of switching conditions, 
183 

electrical circuit, 182-183 
mechanical assembly, 181-183 
use as timing device, 180 
use in single ping ranging exer¬ 
cises, 180 

Range recorder operator training 
elementary range recorder 
teacher, 31, 82-83 
instruction manuals, 24 
model chemical recorder, 31 
QFL tactical range recorder 
teacher, 20, 22-31, 83-86 
QFM torpedo detection modifica¬ 
tion trainer, 50, 186 
recorder trace projector, 31, 86- 
88 

Range recorder teacher, instructor 
training, 22 

Range recorders, modified for 
SRGT monitor recorders, 
179 

R-C oscillator, thermistor-sta¬ 
bilized, 105-107 

Reading and arithmetical reason¬ 
ing test, 12, 43 

Reading test (NavPers 16524), 14 

Recommendations for future re¬ 
search 

audiometer for group testing, 13 
auditory discrimination tests, 13 


BDI trainer improvements, 71-72 
eye-ear-hand coordination test, 

13 

modification of operational bear¬ 
ing recorder, 173-174 
practice attack meter, 132 
practice target transducer crys¬ 
tals, 133, 134 

recorder trace projector, 87, 88 
relative movement visualization 
test, 13 

sonar personnel selection and 
training program, 8, 13, 42- 
43 

Recorder operator trainers 

see Range recorder operator 
training 

Recorder trace projector, 31, 86-88 
Relative bearing animated trainer, 
171 

Relative bearing with magnetic 
ocean demonstrator, 170 
Relative motion visualization 
aptitude test, 17-18 
magnetic ocean demonstrator, 
170 

SASAT slide rule, 33 
Relative movement test, 17-18 
Repeater targets, 32-33 
Resistance-capacitance stabilized 
oscillator, SASAT A, 105- 
107 

Reverberation simulation 
by inverse TVG, 60-61, 64 
by phase modulated simultaneous 
lobe comparison units, 60 
by program cams, 61 
disadvantages of electronic sim¬ 
ulation, 82-83 

in group operator trainer, 74 
in OTE-2; 60-61, 63-65 
in OTE-4; 92-94 
Rochelle salt crystals 

change in sensitivity with tem¬ 
perature, 133, 134, 136 
use in practice target equipment 
transducers, 133 

RR-1 A/S practice target, 140-141 

SI practice target amplifier, 136, 
139 

51- AB practice target amplifier, 

136, 139 

52- AB practice target amplifier, 

136, 139 

53- AB practice target amplifier, 

136, 139 

S5-AB practice target amplifier, 
136, 146 


RESTRICTED 



INDEX 


233 


San Diego Sound School, 1 
instructions, 34 

sonar maintenance man selec¬ 
tion, 13-15 

submarine sonar training pro¬ 
gram, 47-49 

Sangamo attack teacher 

auxiliary assisting ship pro¬ 
jector, 96-98 

auxiliary attack teacher azimuth 
grid, 99 

auxiliary depth charge pattern 
recorder, 32, 99-101 
connection to BDI trainer, 71 
improvements, 32 
OTE-4 signal injector for asso¬ 
ciated BDI equipment, 36, 
89-95 

OTE-8 attachment, 36, 57, 68 
Sangamo sound range recorder, 
85-86 

SASAT A, 33, 102-108 

bearing control circuits, 107 
description, 102-108 
disadvantages, 104-105 
echo delay and keying circuits, 
107-108 

echo oscillator circuits, 105-107 
instructor’s manual, 104 
modification for BDI, 105 
output circuits, 108 
regulated power supply, 108 
SASAT slide rule, 33, 105, 123 
WEA-l and WEA-2 selsyn 
adapter units, 121-123 
SASAT B, 33, 109-121 
advantages, 121 

component analyzers, 114, 115 
control panel, 114 
echo delay and timing circuit, 
112 

echo simulator circuits, 112-114, 
117-121 

model I, 109-114 
model II, 114-121 
operation of firing circuit, 112 
own ship’s speed motor, 115 
ranging mechanism, 117 
SASAT slide rule, 33, 105, 123 
Scoring systems, sonar personnel 
achievement tests, 21-22 
Search procedure training 
lantern slides, 28, 56 
phonograph records, 24-28 
Seashore measures of musical 
talent 

disadvantages for sonar operator 
selection, 11 


pitch, intensity and tonal mem¬ 
ory tests, 9, 16 
time and timbre test, 12, 17 
Selection of sonar personnel 
see also Aptitude tests 
ASW maintenance personnel, 1, 
13-16 

ASW officers, 1, 9-13, 16-18 
ASW operator selection, 1, 16-17 
submarine operators, 4-5, 40-44 
Selsyn adapter units, WEA sonar 
keying unit, 122-123 
selsyn unit, 121-123 
Sensitivity of crystals, variation 
with temperature, 133, 134 
Ship recognition training, peri¬ 
scope trainer, 56 

Ship sound recordings for radio 
sono buoy training pro¬ 
grams, 37-39 

Shipboard antisubmarine attack 
teachers 

see SASAT A; SASAT B 
Shipboard trainers for sound 
operators and attack teams 
echo injector, 33, 102-104 
SASAT A, 102-108 
SASAT B, 109-121 
Signal generator, BDI adjustment, 
157-160 

circuits, 158-160 
description, 157-158 
requirements, 158 
Simulated transducer, group oper¬ 
ator trainer, 79-80 
Simulator coils 

in artificial sonar projector, 148- 
149 

in OTE-2; 60-61, 66 
in OTE-4; 91-92 

Simultaneous lobe comparison 
(SLC) demonstration unit, 
60-61 

Slide films 

angle-on-the-bow estimation, 56 
radio sono buoy training, 37-39 
Slide rule for relative bearing and 
range rates, SASAT A, 33, 
123 

Smoke signal for submarine 
marker buoy, 133 
Sonar Bulletin, 24 
Sonar Equipment Log, 24 
Sonar History Record, 24 
Sonar Maintenance Handbook, 24 
Sonar maintenance personnel train¬ 
ing 

instruction manuals, 24 
submarine school program, 49 


Sonar maintenance training de¬ 
vices, 148-161 

artificial sonar projector, 148- 
155 

BDI adjustment signal genera¬ 
tor, 157-160 

BDI dynamic demonstrator, 156- 
157 

JP amplifier demonstrator, 160 
trouble injectors, 161 
Sonar officers 

ASW officer training, 19, 36-37 
selection methods, 1, 16-17 
submarine officer training, 47-49 
Sonar operator selection 

see ASW sonar operator selec¬ 
tion; Submarine sonar oper¬ 
ator selection 
Sonar operator training 

see ASW sonar operator train¬ 
ing; Submarine sonar oper¬ 
ator training 

Sonar pitch-memory test, 11-18 
correlation with relative move¬ 
ment test, 18 
description, 17 
reliability, 17 
Sonar projector, artificial 

see Artificial sonar projector 
Sonar training barge, ComSub- 
TrainPac, 46 

Sonar-radar training barge, 47 
Sono buoy 

see Radio sono buoy training 
programs 

Sono Buoy School, 3, 38 
Sound discrimination drill exer¬ 
cises, ERGT, 32 
Sound injector 

for conning officer attack teacher 
modification, 196-197 
for Mark I attack teacher, 56 
Sound Material Handbook, 24 
Sound range recorder 

see Range recorder operator 
training 

Sound recognition group trainer 
(SRGT), 47-49, 175-179 
description, 175-176 
facsimile system, 178-179 
instructor’s station, 176-177 
monitor recorders, 179 
phonograph recordings, 49, 179 
students’ stations, 177-178 
SR-2 antisubmarine practice tar¬ 
get, 32, 141-146 

operating characteristics, 145- 
147 

towing characteristics, 143-146 


RESTRICTED 



234 


INDEX 


SR-5 antisubmarine practice tar¬ 
get, 32, 146-147 
operating characteristics, 147 
towing characteristics, 146 

SRGT 

see Sound recognition group 
trainer (SRGT) 

Stadimeter used with periscope 
trainer, 200 

Standard Submarine Phraseology, 
52-53 

Standard Telephone Talkers’ 
Manual, 53 

Submarine barometer simulator 
circuit operation, 203 
description, 202-203 

Submarine bathythermograph 
training program, 3, 5, 37, 
54-55 

bathythermograph simulator, 55, 
203-209 

classroom demonstrator, 209-210 
field instruction, 54 
instruction books, 37, 54 

Submarine Chaser Training Center, 
Miami, 16 

Submarine marker buoy, 133 

Submarine phraseology standard¬ 
ization, 52-53 

Submarine radar operator train¬ 
ing, 51 

Submarine sonar maintenance 
training, 49 

Submarine sonar officer training, 
47-49 

Submarine sonar operator selec¬ 
tion, 4-5, 40-44 
audiogram studies, 41-42 
propeller noise discrimination 
meter tests, 42 

recommendations for future re¬ 
search, 42-43 
selection test battery, 40 
target discrimination test re¬ 
cordings, 42 

validation of selection plan, 41 

Submarine sonar operator trainers, 
175-192 

barge monitoring equipment, 192 
group listening teacher, 186-192 
noise level monitor trainer, 183- 
184 

range indicator trainer, 180-183 
sound recognition group trainer, 
175-179 

torpedo detection modification 
trainer, 186 

Submarine sonar operator train¬ 
ing, 4-8, 45-51 
JP training program, 45-46 


standard ship’s complement, 40 
synthetic trainers, 175-192 
West Coast Sound School pro¬ 
gram, 47-49 

Submarine Sonar Operator’s 
Manual, 50 

Surface model RR-1 antisubmarine 
practice target, 139-141 
Synthetic targets 

see Practice target equipment 
Synthetic trainers 
see Trainers 

Tactical sound range recorder 
teacher (QFL) 

see QFL tactical sound range 
recorder teacher 
Tactics trainer, pantograph, 39 
Target discrimination recordings, 
42 

TBS, bathythermograph simulator 
see Bathythermograph simulator 
(TBS) 

TDM sonar equipment, training, 
50 

Telephone Talkers’ Manual, 53 
Temperature, effect on transducer 
crystals, 133, 134 

Thermistor stabilized R-C oscil¬ 
lator, 105-107 

Tonal memory, pitch memory test 
for, 11-18 

Torpedo angle solver demonstrator, 
56, 202 

Torpedo data computer, Mark I, 
modified, 193 

Torpedo detection modification 
trainer, 186 
Torpedo noise 

phonograph records, 24-28 
simulation in group listening 
trainer, 192 

Towed submarine marker buoy, 133 
Towed underwater echo-repeaters 
SR-2 practice target, 141-146 
SR-5 practice target, 146-147 
Trace interpretation, BDI, 36 
Trace recognition, sound range re¬ 
corder 

see also Range l'ecorder operator 
training 

oversimplification of trace caused 
by SASAT, 33 

oversimplification of trace caused 
by synthetic targets, 32 
Trainers, 2, 19, 28-35 
see also navies of individual 
trainers 

attack teacher modifications, 32, 
89-101 


for aircraft personnel using 
sonar equipment, 162-166 
for ASW maintenance personnel, 
148-161 

for ASW operators, 57-81 
for range recorder operators, 82- 
88 

for submarine officers, 193-211 
for submarine sonar operators, 
175-192 

practice target equipment, 133- 
147 

requirements, 7 

shipboard trainers for sound 
operators and attack teams, 
102-132 

Training, sonar maintenance per¬ 
sonnel 

see Maintenance personnel, 
training; Maintenance train¬ 
ing devices 

Training, sonar operators 

see ASW sonar operator train¬ 
ing; Submarine sonar oper¬ 
ator training 
Training aids, 2 

see also Instruction manuals; 
Lantern slides for sonar 
training; Phonograph re¬ 
cordings ; Trainers 
motion pictures, 28, 38-39 
slide films, 37-39, 56 
trouble injectors, 49, 161 
wall charts, 53 

Training programs for sonar lab¬ 
oratory developments, 35-39 
bathythermograph program, 37 
BDI program, 36-37 
construction of synthetic 
trainers, 35 

ERSB and DRSB program, 37-38 
MAD program, 38-39 
manuals, 35 

operational research, 35 
training courses, 35 
Transducer, simulated, group oper¬ 
ator trainer, 79-80 
Transducers, sonar, vector anal¬ 
ysis, 149-150 

Transducers for practice targets, 
133-136 

BD-1 transducer, 134-136, 139- 
140 

CD-I transducer, 134-136, 141 
CG-1 transducer, 136, 139, 141 
CJ-1 transducer, 136, 139, 141 
directivity patterns, 134-135 
Trouble injectors, 49, 161 


RESTRICTED 



INDEX 


235 


U2-AB practice target amplifier, 
136, 138, 141-145 

Underwater sound phonograph re¬ 
cordings 

see Phonograph recordings 
University of Pennsylvania, 167 

Villari effect, definition, 213 
Visual aids 

see also Lantern slides for sonar 
training 

magnetic ocean demonstrator, 
170 

motion pictures, 28, 38-39 
slide films, 37-39, 56 
wall charts, 53 
Visual tests 

eye-ear-hand coordination test, 
13 

near vision acuity test, 12 
relative movement visualization 
test, 13 

Voice communications training, 52- 
54, 63 


instruction manuals, 53 
interphone, 53-54 
phraseology and procedures, 
standardization and train¬ 
ing, 52 

telephone talker training, 52-54 
wall charts, 53 

Wall charts, telephone talking 
rules, 53, 54 
Water noise 

interference with practice attack 
meter, 126 

simulated in conning officer at¬ 
tack teacher modification, 
197 

simulated in group operator 
trainer, 74 

Water temperature, effect on 
transducer crystals, 133, 134 
WCA sonar equipment 

ComSubsLant sonar-radar train¬ 
ing barge, 47 

range indicator trainer, 180-183 


training recordings, 50 
with group listening teacher, 47, 
186-188 

WEA-1, -2 selsyn adapter units 
keying unit, 122-123 
selsyn unit, 121-123 

WEB sonar training, group listen¬ 
ing teacher, 47 

West Coast Sound School, San 
Diego, 1 

curriculum revision, 20 
instructors, 34 

sonar maintenance man selec¬ 
tion, 13-15 

submarine sonar training pro¬ 
grams, 47-49 

Woods Hole Oceanographic Insti¬ 
tution, 3, 37, 54 

X-cut Rochelle salt crystals 

effect of temperature on sensi¬ 
tivity, 133, 134, 136 
use in practice target equipment 
transducers, 133 


RESTRICTED 















































































. 
























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• • 










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HEADQUARTERS EIGHTH NAVAL DISTRICT 


NEW ORLEANS 40, LA. 




REFER TO NO. 


26 July 1962 


Library of Congress 

Science and Technology Project 

Washington 25, D. C. 

Gentlemen, 

The enclosed books, copy no 143, Summary Technical Report of Division 
6, NDRC, Volume 4, H Methods and Devices Developed for the Selection and 
Training of Sonar Personnel" and copy no 144, Summary Technical Report of 
Division 6, NDRC, Volume 8, "The Physics of Sound In The Sea" were found 
in a locked file cabinet here. They are not needed by this office and 
are therefore returned. 


Respectfully, 



Lieutenant, U. S. Navy 
Acting District Reserve 
Electronics Program Officer 



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RETENTION 
Report Receipt 


LIBRARY OF CONGRESS 
SCIENCE AND TECHNOLOGY PROJECT 
WASHINGTON 25, D. C. 


TO: Commandant, 8th a aval District 
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DATE 

AUG 161948 

Reference 

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S.T.R. Div. 6, Vol. 4 

TRAINING METHODS AND DEVICES 

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lsiq ivavn h lg saiouc 

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Receipt Acknowledged By _ Date. 













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RETENTION LIBRARY OF CONGRESS 

Report Receipt SCIENCE AND TECHNOLOGY PROJECT 

WASHINGTON 25, D. C. 

DATE 0 , 

AUG 161948 


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Reference 


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Date Received o 

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Serial No. 2 3 5 0 0 


Dlst. File No. 

Subject: AlO/fcll-1 

8-16-48 - HETEETI N REPORT RECEIPT - Fading S.T.R.Dir 6, 
Vo 14, TRAINING METHODS AND DEV ICES •DEVLLOPE2) FOR TH E SELEC¬ 
TION AND RAINING OF SONAR PERSONNEL* Cpy No 143 . 

\ 

FROM: LIBRARY OF CONGRESS,SCIFNCEP8?/lH<^GHNOLOGY 2ROJECT 


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RdSCaRCH AnD DeVRuOPMEnT r-U.hRjj 


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rector , search Grcuo 

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Director, 

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ion (Cod 

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Director, 

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i i ') 


CO, Office of .aval Research Branch Offices 


branch Office 
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branch Office 
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Civilian OinC 

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